Planning Your Project

Remains of an Eared Pillbox, Reighton Gap 2016 © C. Kolonko

Here we are again, at long last, with another blog post! This time I will focus on planning your field work and things to take into consideration before heading out; the focus being the most basic form of non-invasive field recording. I will eventually cover non-invasive field recording techniques, so hold in there! Be prepared, this is a long ‘un!

Disclaimer- As always, I am not in any way responsible for any issues that arise as a result of using this guide.

Where are you now?

By now, you should have conducted some desk based research focussing on your chosen survey area. At the very least, you will have consulted available sources of information, such as the Defence of Britain project data and Historic Environment Records via Heritage Gateway. You may have also used aerial photographs to identify unrecorded features such as trenches, roadblocks and anti-tank ditches (See previous blog). You will need to have a clear understanding of what you expect to find and where you expect to find it.

If you haven’t consulted available HER records, via Heritage Gateway, now is a good time to do so. This is useful as it will allow you to assess current records and identify ‘information gaps’. Some HER records relating to Second World War defences are very basic and sometimes just state the site’s location and type. The main aim of this blog series is to enable you to fill some of these information gaps with your research and field work. Remember to make a note of the HER record numbers at this point as these will come in very useful later (It can be tricky to match HER records to your field records after you have completed your survey).

If you have done all this, then you’re good to go!

Aims and Objectives

Outlining your aims and objectives is always the best starting point; there’s no point conducting fieldwork if you don’t know why you’re doing it, or how you’re going to do it.

Your aims (a goal you wish to achieve) and objectives (the steps you will take to fulfil the aims) should be clear and you should be confident that you can fulfil them.

You should start by considering:

What? What do you want to do? What is your focus? What defences do you want to record? Do you want to record the current condition of known defences, record un-recorded features, assess defence strategy or aim to cover all these tasks? What will you do with your results and data? What sources of information are available to you?

Why?  Why do you want to record Second World War defences? Why are the defences in your survey area significant? Do you want to help build up a better understanding of the defences in your survey area and create a detailed record?

When? When will you conduct your field work? Always consider how long you intend to spend recording and how much time you have available. You may be surprised by how long certain tasks will take.

How? How will you complete your allotted tasks? Do you have the necessary time and resources? Do you have the required skills?

Here’s an example, based on my own research and field work-

What? This project aims to seek a better understanding of Second World War defences in Filey Bay and to create a lasting record. The project will:

-Identify and record extant, lost and un-recorded defences; including earthworks, passive defences and concrete remains.

-Assess the current condition of surviving defences.

-Create a record for each feature; consisting of an accurate 10-figure grid reference, detailed site description, condition assessment and photographic survey.

-Assess the defensive strategy employed and explain the placement of the defences within the landscape.

Why? This project will help to create a better understanding of the significance of the Second World War defences of Filey Bay, and create a detailed record of extant and lost defences. Investigating the defensive context of these defences, by considering their deployment within the landscape, will help to explain why these defences where constructed and how they would have been used in the event of an invasion. The high attrition rate due to coastal erosion continues to take its toll on the surviving defences in this area. Recording these defences thoroughly will help to preserve them in the record for future generations.

When? Field work will take place in October 2017; including a field survey to be undertaken over three days, considering the large survey area. Further condition monitoring will be conducted on a yearly basis following the completion of the field survey.

How? Research and field work will be conducted by Chris Kolonko. A detailed Desk Based Assessment will be conducted prior to the field survey, to identify relevant sources of information that will aid the interpretation of the surviving defences and help identify their current locations. A Level 1 or 2 survey of each feature will be conducted to record location and condition, as well as assess the feature’s function and the strategy behind its deployment. Survey results will be assessed, interpreted and presented using an appropriate GIS package. All data will be compiled into a relevant format to aid inclusion within the Historic Environment Record.

Don’t worry! This example was meant to be detailed, just to give you an idea of some things you can take into consideration when planning your field recording.

Contacting the HER/SMR

The Heritage Gateway contacts page

The Historic Environment Record or Sites and Monuments Record curate information about historical and archaeological sites within a county or unitary authority. HERs/SMRs often curate a database of historic and archaeological sites that is used as a public information service or research tool. HERs often provide information to planning authorities, developers, the public utilities, conservation bodies and landowners, to ensure significant historic or archaeological sites are preserved and maintained where necessary.

Adding information to a local HER/SMR is extremely important as the information is used to inform local planning decisions. Highlighting the importance and significance of surviving defences in the record is the first step to ensuring their survival. Also, if a site is to be demolished, or at risk from coastal erosion, your information can ensure a site is ‘preserved in the record’ once it is gone. Therefore, detailed recording and interpretation is now required.

Once you have decided upon your aims and objectives, and identified information gaps, it is time to contact your local Historic Environment Service to discuss your project, decide what information would be of use and decide upon data formats that will allow your information to be recorded within the HER.

Click here for HER/SMR contact details

Surveying Your Survey Area

Filey Bay

It is always wise to investigate your survey area before you start your field work. This will allow you to identify areas of public access, potential landowners, convenient places to park and somewhere to take shelter and get a hot drink if the weather changes. This is useful if you don’t know the survey area very well.

You can assess your survey area with an Ordnance Survey map, Magic Map or Google Maps; keeping an eye out for public carparks, conveniences, and places where you can take shelter if bad weather sets in.

Depending on the size of your survey area, you may wish to split up the area into manageable chunks. Defences are usually dispersed and you may find yourself covering a greater distance than you may think. It’s best to plan ahead and dedicate a number of days to a field survey to give yourself plenty of time to record all the information you will require; there’s nothing worse than rushing field work.

If you are working on the coast remember to find out the tide times for your date of survey.

Public Access and Landowners

North Yorkshire County Council Definitive Map- Filey Bay

Always identify areas of public access, and secure landowner consent before any field recording.

You will need to identify public footpaths and rights of way that give you access to the areas you wish to investigate. You can find online versions of most Definitive Maps which show current public footpaths and rights of way, courtesy of the brilliant Geograph website-

You will need to gain express landowner consent to access any private land. Private land doesn’t need to be marked with a sign, so if you don’t see a sign it doesn’t mean you have free access. Keep an eye out for local farms and potential landowners while doing your site evaluation and stick to public footpaths. It is always best to conduct a preliminary walk-over of your site to check accessibility and to gain landowner consent; this may involve knocking on some doors. It should go without saying, but always be courteous when meeting landowners, explain the reasons why you would like to access their land and exchange contact details.

If you are granted access, arrange a convenient date to conduct your site visit, especially if fields are under crop or being used by grazing livestock. If the landowner doesn’t allow you to access their land that’s the end of the matter; don’t trespass regardless. This is un-professional and will only work against you in the future.

Remember- You will still need landowner consent to access features that don’t sit directly next to a public footpath. If you can’t secure landowner consent, don’t leave the footpath. You can still identify the site’s type, make a condition assessment and interpret the site’s defensive location from a distance.

Also, Don’t dig anything up, especially if you are not a qualified/experienced archaeologist and if you don’t have the permission of the landowner. You will cause damage and get into serious trouble. Digging ANY site without the express permission and guidance of the local Historic Environment Service, landowner consent and the supervision of a trained archaeologist will result in you committing a Heritage Crime.


Basic Equipment

You will need some basic kit to conduct your field recording. Most of this can be found around the house and more specialist equipment can be purchased relatively cheaply online.

Here’s my list of recommended kit-

An Ordnance Survey Map- A 1:25,000 scale Ordnance Survey map will help you to navigate your site.

A notebook- Useful for writing down observations, keeping track of project reference numbers and photographs.

Recording forms- Recording forms are used to record your field observations in a set format and make writing up your records a lot easier. You’ll find out more about these in the next blog.

A clipboard- Handy for stopping your recording forms blowing away. A clipboard also gives you something to rest on while filling out the forms. The MDF type are the best.

Pencils, pens and other stationery- Always bring along more than one pen; you can always guarantee a pen will stop working. Pencils are useful for making field sketches. You will also need a pencil sharpener and eraser. Keep this little lot in a sturdy pencil case.

A compass- Very useful for recording the orientation of surviving remains.

A digital camera- This can be a simple digital camera wirh an optical zoom or a DSLR with flash. I don’t recommend using mobile phones to take your site photographs, but at a push they can be used.

Binoculars- Binoculars will help you assess features from a distance, especially in areas where access isn’t possible.

Ranging poles and photo scales- Two 1m ranging poles and a 30cm photo scale are a basic requirement when taking photographs and help give a sense of scale.

A tape measure and/or reel tape- A handheld tape measure and reel tape are essential for measuring the features you find. I use a simple hand-held tape measure and a 30m reel tape.

A rucksack or haversack- You’ll need a sturdy bag to carry all of your equipment in. as well as food, drink and additional clothing.

Optional equipment

A handheld GPS reader- This is a great piece of kit to have and makes taking grid references much easier while in the field. However, they can be inherently inaccurate. There are some effective smartphone apps that can provide great results; again, I’ll cover these in the next blog.

Health and Safety

You will need to make sure you are working safely while on site to ensure the minimum exposure to risk and personal injury. Remember, I am not responsible if you do get injured as a result of using this guide.

Ensure you have a sturdy pair of waterproof walking boots with sufficient ankle support. Take additional layers of clothing just in case the weather turns cold and always take a waterproof jacket. You can always take off extra layers.

Let someone know where you are going and when you expect to get back and always work with at least one other person; an extra set of eyes always comes in useful. Ensure you take a fully charged mobile phone and check that you will have phone coverage within the survey area.

Don’t enter dilapidated structures or structures that you can’t see inside. Though entering pillboxes to investigate their fixtures and fittings can be useful, it is not worth doing if you risk injury. Surviving pillboxes are often flooded and contain a whole range of nasties. If you can’t see where you’re going, don’t enter.

I recommend you have a read of the site safety information on the Home Front Legacy 1914-18 website-

For specific H&S advice when working in coastal areas consult CITiZAN’s great advice here-

Further Information

You can find more detailed information about project planning  and putting together a project design on the ISGAP website-

The End

Right, that’s the end of this blog. This should give you something to think about before heading out into the field. Remember, the whole point of this is to assess and augment current records and help us to better understand the remaining defences.

Take some time to digest the information and I’ll see you next time for another instalment of this blog series. Maybe I’ll throw in a follow up blog or another Pillbox Myth in the meantime, who knows?

Over and out!

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Planning Your Project by Chris Kolonko is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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Pillbox Myths #1

To ensure a steady flow of articles through this blog I’ve come up with a new regular piece focussing on ‘pillbox myths’. From time to time someone will state a ‘fact’ about pillboxes that quite simply isn’t true and is in fact a myth. Some of these myths have now entered common knowledge and are readily accepted as true. This is my attempt to debunk some of the most common myths surrounding pillboxes (and maybe vent a bit).

Bring on the myth!

‘All pillboxes are protected/listed/scheduled by Historic England/English Heritage/The National Trust etc. etc.’

A couple of weeks ago someone on a popular social media platform stated categorically that the recent preservation of a pillbox, within a new housing estate, was not due to the work of the local planning department, HER  or the developers, but was because ‘all pillboxes are listed by English Heritage’.

This annoyed me somewhat as the statement had no factual basis and dismissed the hard work of those who had ensured this structure’s preservation; especially when the developers could have bulldozed the pillbox and built houses on the space. This spurred me on to write this post.

The Truth

Every so often I encounter posts on social media by individuals wishing to learn more; enquiring whether pillboxes, and other Second World War defences, are all subject to statutory protection based solely on their perceived importance.  Though some pillboxes are protected through scheduling and listing; often because of their rarity, level of preservation or historical significance (and the fact that someone took the time to apply to have the structure protected), the majority are not protected by listing/scheduling. This means that it is often up to the landowner whether to retain or demolish them. In England scheduling and listing of historic buildings falls under the remit of Historic England; it is a common misconception that English Heritage are still responsible for this process.

Unfortunately, if people do believe that all pillboxes are protected, then the survival of significant/important remaining pillboxes can be put at risk, as people won’t take any action when a pillbox is threatened with demolition.

But all hope is not lost! Anyone can apply to have a historic site or building listed or scheduled. This can be done with the online form available on the Historic England website. The process is very straightforward and you don’t need to be a heritage professional to submit an application.

Information on listed buildings can also be added to through the ‘Enriching the List’ project and this is well worth looking into as well.

Countering The Myth

The best way to counter this myth is to simply explain that most pillboxes are not protected in anyway whatsoever; often the expense of demolition and sympathetic landowners are the only thing protecting a surviving pillbox. Pointing people in the direction of the online listing application form is also worthwhile. Who knows? More pillboxes, and other defences, may acquire listed/scheduled status!

Find Out More

You can find out more about scheduling and listing via the links below.

What is listing?

Scheduled Monuments

Listed Buildings

How We Determine Whether a Historic Building or Site Should be Protected (Thanks Ken)

How To Get Historic Buildings or Sites Protected Through Listing

Quick Update

I have just started writing the follow up to my Investigating Aerial Photographs blog post! This upcoming blog post will focus on the process of planning a basic field recording recording exercise . Watch this space!

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Investigating Aerial Photographs

ROYAL AIR FORCE OPERATIONS IN THE MIDDLE EAST AND NORTH AFRICA, 1939-1943. (ME(RAF) 2402) Airmen photographers inspect developed reconnaissance film from a Type F.24 aerial camera outside a photographic trailer at a landing ground in Egypt. Copyright: © IWM. Original Source:

To follow on from my blogs covering the basics of researching Second World War defences in the UK, I’ve decided to cover the use 1940s Aerial Photographs to identify defences in your research/survey area.

I’m currently attempting to make sure these blog posts turn into a coherent guide that follows the process I use to research and record sites. I’ll try my very best not to get distracted or go off on a tangent along the way.

I intend to cover aerial photograph interpretation in a lot more detail when I eventually get around to writing a book (which will probably never happen!). So, I’ve decided to focus on a small sample of the more ephemeral defences you might encounter. This case study will also act as an introduction to these defences.

A Quick Disclaimer

As usual, I am not responsible for any issues that may arise as a result of using this case study.  I am currently very concerned about the issue of people trespassing on private property to access surviving sites. It is very likely that some of the sites presented in this blog sit on private property; so don’t trespass to view them! The landowner has a right to privacy and the right to not have their property violated or damaged. Trespassing has a knock-on effect on the survival of remaining sites and if people are trespassing to view defences ‘up close’, there’s the possibility that sites will be damaged as a result, or even demolished by the landowner.  Trespassing also hampers the work of individuals with a genuine interest in investigating, recording, interpreting and preserving the archaeological remains of 20th century defensive landscapes. Always gain express landowner consent BEFORE accessing a site. If your site sits within land accessible by public footpath don’t leave the footpath to take a closer look, unless you have the consent of the landowner. It’s also worth noting that private land does not need to be signposted; if you don’t see a sign it doesn’t give you the right to access. Always do your research, identify potential landowners and gain the relevant permissions in advance of any field work. In fact, it’s best to arrange to visit the landowner. This way you can explain why you would like to access their land, share your information, and discuss the site with the landowner. If you don’t get permission don’t access the land regardless.

Aerial Photographs

ROYAL AIR FORCE FERRY COMMAND, 1941-1943. (HU 93054) Vertical aerial view of RAF Hendon, Middlesex, soon after the completion of the new 1,159 yard secondary runway and extensions to the main runway. These overdue improvements were instituted following the transfer of Hendon from Fighter Command to Ferry Command on 1 April 1942, in order to handle the increasing aerial traffic and the larger aircraft employed. These included the Douglas Dakotas of N… Copyright: © IWM. Original Source:

Aerial photography is used extensively within archaeology to identify sites in a given area. Aerial photographs can reveal cropmarks and low lying earthworks which are frequently missed on the ground.

Aerial photography is also a key aspect in identifying forgotten or lost Second World War defence sites. 1940s aerial photographs of your chosen area may reveal unrecorded or lost defences, as well as defences that don’t often survive; such as trenches, barbed wire obstacles or roadblocks. Trenches and barbed wire were an integral and important part of the defensive landscape; identifying their location and presence will help you to build up a more in depth picture of the defences and defensive strategy.

Consulting aerial photographs as part of your Desk Based Assessment will allow you to highlight specific areas to focus on during your field work or initial walkover survey. The aim of your research should be to build up a picture of the defences in your area, using available documents and data. At this point you should already be building up a picture of the 1940s defences, and should already have a good idea of the range of defences that may survive and those that may have been destroyed.

Sources of aerial photographs

Google Earth Pro

I’ve mentioned Google Earth Pro in my previous blog. You’ll be pleased to find that 1940s aerial photographs for parts of the UK can be accessed via Google Earth Pro!

Simply press this button here-

Google Earth Historical Photography button

Sometimes you will need to slide the date slider back to 1940. Once you have done this, you’ll be instantly transported back to wartime Britain! It’s as simple as that! You can now start exploring your survey area, as long as you know what you’re looking for!

Please be aware that Google Earth doesn’t use the UK National Grid Reference system, so you’ll have to convert any grid references into coordinates, and vice-versa, using an app like the Grid Reference Finder.

Your local Historic Environment Record will use UK National Grid Reference system to record locations.

Historic England

As mentioned in a previous blog post, Historic England hold an archive of over 4 million aerial photographs; 95,000 of these can be viewed on the Britain From Above website.

Many of the 1940s aerial photographs are held within Historic England’s archives in Swindon. You can view prints free of charge in their Search Room.

For more information visit the Historic England website here

If travelling to Swindon isn’t possible, then you can request a free search of the aerial photograph archive; this will take around 15 days.

When requesting a search for your area it is useful to provide an accurate National Grid Reference for the centre of your site, depending on the size of your research/survey area.

This free search will provide you with a list of all the aerial photographs for your area.

Look for aerial photographs of your area dating from May 1940 and later. Aerial photographs from before May 1940 may not reveal Second World War defences, as construction didn’t commence until after the appointment of General Ironside as Commander-in-Chief of the Home Forces, on 27 May 1940; this date also marks the start of Operation Dynamo (The Dunkirk evacuation).

Once you have decided which aerial photographs you require, you can request copies. Photocopies are available, including enlargements of areas of interest.

Low and high resolution digital copies of the aerial photographs can also be purchased, but please be aware that these can be quite costly; however, they are invaluable when conducting a detailed examination of defence works.

You can find an up to date list of prices here.

Be aware that you will need permission from Historic England to reproduce the images or use them for anything other than personal study.

The Historic Environment Record/Sites and Monuments Record

Your local Historic Environment Record (HER) or Sites and Monuments Record (SMR) may also retain historical aerial photographs. This won’t be applicable to all HERs/SMRs, but it’s always best to make contact to check, and make them aware of your research/fieldwork. Your local HER should be able to provide valuable advice, or point you in the right direction. You can find the contact details for your local HER/SMR here

Site Types & How To Identify Them

THE BRITISH ARMY IN THE UNITED KINGDOM 1939-45 (H 3307) Pillbox camouflaged as a petrol station in Felixstowe, 24 August 1940. Copyright: © IWM. Original Source:

This brings us onto actually using aerial photographs to find Second World War defences. I’ve provided some examples that I’ve picked out of Google Earth using the 1940s aerial photographs from Kent and Cambridgeshire. Hopefully, this will help you to ‘get your eye in’.

Anti-Tank Pimples and Cubes

Anti-tank cubes and pimples were one of the most widely constructed forms of anti-tank defence. They could be found stretching for miles along the coast, as well as inland and were used to impede the movement of tanks and other vehicles across open ground.

THE POLISH ARMY IN BRITAIN, 1940-1947 (H 5493) Engineers of the 1st Rifle Brigade (1st Polish Corps) constructing beach defences at Tentsmuir in Scotland. The concrete blocks were used as anti-tank obstacles. Copyright: © IWM. Original Source:

The anti-tank cube, as the name suggests, was a large cube of reinforced concrete, often measuring between 1m-1.5m in width and approximately 1.5m in height. Many variations in height and width can be encountered. The cube was often reinforced with a single length of RSJ or railway track in the centre. They were cast in-situ using poured concrete and wooden shuttering (A wooden mould), but examples shuttered in brick and corrugated metal are known.

The anti-tank pimple on the other hand was smaller in comparison; looking like a flat-topped pyramid with a squared off base. These are around 90cm in width and 60cm in height and are frequently referred to as ‘Dragon’s teeth’.

Anti-tank cubes and pimples visible on the Isle of Grain in 1940

Anti-tank cubes and pimples show up very prominently on aerial photographs. They often appear as double lines of light coloured ‘blotches’ (see aerial photographs below), running in parallel.

Areas where they are commonly found include:

  • Long, exposed stretches of beach, especially around beach exits. Sometimes they are found at the base of cliffs; I believe this was done to prevent vehicles on the beach from seeking cover at the base of cliffs. The anti-tank cubes would ensure the vehicles stayed within the fields of fire of weapons employed to cover the beach.
  • Running parallel to roads to stop vehicles from leaving the road when attacked. This is often a sign of a prepared ambush and roadblock in the area.
  • Inland defences such as stop-lines and anti-tank island/defended locality/nodal point defences.

Anti-tank pimples adjacent Dover Castle


ANTI-INVASION DEFENCES IN BRITAIN DURING THE SECOND WORLD WAR (H 2465) Tank traps in a street in Farnham, Surrey. Copyright: © IWM. Original Source:

Roadblocks were employed to hamper the movement of tanks and other vehicles along the road network. Similar blocks were also employed on the rail network, as tanks can move just as well on the track bed as they can by road; these are known as ‘rail blocks’. There were several roadblock types employed during the war, two of which can be spotted on aerial photographs.

The first type of roadblock consisted of two large concrete blocks, similar to anti-tank cubes in appearance but substantially bigger, placed on each side of the road. The blocks also projected into the road, which significantly restricted the width of the road itself. The concrete blocks were slotted to accept RSJs (girders) or railway track which, when in place, ran across the road to block it.

THE HOME GUARD 1939-1945 (H 7330) The Home Guard: Home Guards erecting a road barrier during an exercise held in the north of Scotland. Copyright: © IWM. Original Source:

The second commonly encountered roadblock is the socket type. This involved cutting a series of holes into the road surface, into which RSJs or lengths of railway track were inserted. The holes in the road were fitted with a removable concrete cover. This ensured that car and bike tyres didn’t get damaged and also stopped people twisting their ankles in them during the blackout.

THE HOME GUARD 1939-45 (H 15191) Home Guard soldiers in York prepare a roadblock by inserting metal girders into pre-dug holes in the road, 2 November 1941. Copyright: © IWM. Original Source:

You may be relieved to find that these roadblocks can be spotted from the air.

The concrete blocks of the block type roadblocks look very much like anti-tank cubes from the air. You will see in the image below that they are substantially bigger and can be seen flanking the road in pairs. You may also spot them in gaps within lines of anti-tank cubes in areas where access was required or where they intersected a road.

Three block type road blocks covering a road in West Hythe

The socket type roadblock appears as a series of light patches in the road surface; these are often evenly spaced and stretch across the road. They will often be sited near to a pillbox or spigot mortar emplacement. Using the locations of defences you have gathered from the Defence of Britain records may help you pinpoint a roadblock and vice-versa.

Socket type roadblocks in Dover, 1940

Roadblocks can often be found:

  • Near to bridges crossing viable anti-tank obstacles suck as river and deep railway cutting.
  • Covering road intersections and crossroad.
  • Defending the road and rail approaches to villages, towns and cities.

Roadblocks seldom survive today, especially the socket type as they were removed in the post-war period or simply tarmacked over during road repair and improvement.


THE BRITISH ARMY IN THE UNITED KINGDOM 1939-45 (H 2702) A soldier of the 4th Battalion, The Royal Norfolk Regiment, mans a trench near a pillbox at Great Yarmouth, 31 July – 2 August 1940 Copyright: © IWM. Original Source:

Trenches are very much overlooked and underrated when it comes to defences of the Second World War. Trenches were highly important and actually afforded a greater degree of protection than pillboxes. Pillboxes would be accompanied by a supporting network of trenches; these would cover the pillbox’s blind-spots and provide a greater field of fire for the supporting infantry outside the pillbox.

Trenches come in many shapes and sizes, with the smallest ‘weapon slits’ accommodating two men through to more substantial earthworks capable of sheltering up to a platoon of soldiers (around 30 men).

Second World War trenches tend to be more sinuous and less extensive than their First World War predecessors, though you may spot angular or crenulated trenches dating from the Second World War. These crenulated/angular trenches generally consist of a single line of trench which lacks additional supporting trenches to the rear and the distinctive via zigzagging communication trenches, commonly found on First World War era trench systems, will also be absent.

Substantial semi-crenelated trench, Dover

It can be very difficult to tell the difference between a trench and existing field boundary. A trench will often have a visible mound to its front and rear; known as a ‘parapet’ (along the forward edge of the trench in the direction of fire) and ‘parados’ (along the rear of the trench). See the image below.

Beach defence fire trench, Birchington-on-sea

Freshly dug trenches are quite easy to spot as they will often have the lighter coloured spoil deposited to their front and rear (See first trench image and example below for comparison).

Sinuous trench with signs of spoil, Dover

Often, these trenches will be found apparently isolated in the landscape, and it’s always a good idea to check the top of cliffs and escarpments that sit to the rear of a beach. Another good place to look is within the forward edge of tree-lines and wooded areas.

Substantial trench system and pillbox following an established tree-line, atKingsdown.

Another interesting form of trench is the anti-glider trench. These earthworks were constructed to deny land that could be used by the enemy to land gliders. They often consist of linear ditches with a segmented earthen bank, and look something like this-

Anti-glider trenches at Great Stonar

Anti-tank ditches

THE BRITISH ARMY IN THE UNITED KINGDOM 1939-45 (H 2473) Anti-tank ditch near Farnham in Surrey, 24 July 1940 Copyright: © IWM. Original Source:

Anti-tank ditches, funnily enough, were ditches used to halt the movement of a tank. There were a number of different designs, which I may go into at a later date. Machine cut anti-tank ditches appear on aerial photographs as  long, straight sections of ditch with traverses set at regular intervals. These deliberate earthworks often cut through pre-existing features, such as field boundaries, and are highly visible. The traverses of the anti-tank ditch are often covered by a fixed defence such as a pillbox, anti-tank gun position, trench or spigot mortar position.

Machine cut anti-tank ditch, Great Shelford, Cambridgeshire

Many pre-existing earthwork, such as drainage ditches, were modified to act as anti-tank ditches. These can often be identified by redeposited spoil along their length as well as their proximity to other defences.

Anti-tank ditch using a modified existing earthwork and block type road blocks, Dover

Barbed Wire

INVASION DEFENCES IN THE UNITED KINGDOM (H 2187) Concertina wire defences along the sea front at Sandgate, near Folkestone in Kent, 10 July 1940. Copyright: © IWM. Original Source:

Barbed wire was deployed liberally throughout the landscape. Following the Dunkirk Evacuation, it was one of the few resources the Army had in abundance. Barbed wire entanglements, also known as concertina wire or Dannert wire, were sited to hamper the movement of attacking infantry and also used ensure infantry didn’t get within grenade throwing range of defensive positions. Barbed wire was often covered by withering fire from a flanking trench or machine gun position, otherwise the attacking infantry could walk right up to it and breach it without any trouble (which kind of defeats the whole point of an obstacle!).

Extensive barbed wire entanglements surrounding a military installation, St. Margaret’s Bay, Kent

Barbed wire defences are especially overlooked, very much like trenches, but play a vital role in the landscape of defence.

Barbed wire looks very different to hedgerows and field boundaries; it is a lot darker and semi-transparent in appearance. The images show some classic examples of barbed wire entanglements during the 1940s.

Barbed wire entanglement surrounding a defended locality, St. Margaret’s Bay, Kent

The End

So, that brings me to the end of this blog. Hopefully you will find it useful and not realise that I ran out of steam towards the end. As I mentioned at the beginning, I do hope to cover aerial photograph interpretation in a lot more detail in the future as part of a publication, if the opportunity arises.

Aerial photographs are a great resource that will help you discover the wider context of your chosen site.

Be sure to follow me on Twitter @ckolonko

Over and out.

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Investigating Aerial Photographs by Chris Kolonko is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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Starting Out: Part 2

As my first blog post on ‘Getting Started’ has proven surprisingly popular, I have decided to write a follow-up; following some great feedback on my original blog post.

This post will cover further sources of information you can use to investigate and research Second World War military defences in your local area. It’s also worth noting that many of these sources can be used to investigate much earlier sites. However, as I’m obsessed with stuff made of concrete, the Second World War will be the main focus once again.

Maps and Aerial Photographs

© Google Earth

© Google Earth

Maps and aerial photographs are another wonderful resource for investigating Second World War defences.

Maps can be used to gain an idea of how the landscape appeared during the 1940s; especially when investigating the relationships between defences and vehicular communication systems: such as roads, railways and canals.

Aerial photographs are frequently used to investigate the modern landscape for historical and archaeological features: including crop marks, standing remains, ruins and historical landscape features; e.g. ancient field boundaries. Historic aerial photographs are great for investigating Second World War sites ‘as they were’.

Conveniently, there are a number of readily available (And free!) on-line resources which you can use to investigate historic maps and modern aerial photographic images.

National Library of Scotland Map App

NLS Map App

NLS Map App

The best place to view historic maps is the National Library of Scotland’s Map Images app. This on-line map app allows you to view a wide range of historic maps; from 1888 OS maps, through to OS maps from the 1950s and 60s. There are many other maps available; too many to list here.

I find the ‘Explore Georeferenced maps’ function particularly useful when investigating buildings that were requisitioned during the war, or buildings which still remain that previously had a military function.

The ‘Change transparency of overlay’ tool makes it possible to fade in, and fade out of a modern aerial image; allowing you to quickly see whether a building on the historic map survives today or vice versa.

A neat feature of the app can be found in the bottom right hand corner. As you move the cursor across the map, the 8-figure National Grid Reference is displayed. You can write this grid reference down and use it when searching Heritage Gateway and other websites that allow you to search by grid reference.

The NLS map app also features a ‘Side by side’ feature which displays a modern and historic map ‘side by side’. This, again, is great for exploring current and historic sites.

I won’t cover all the functions of this app as there are so many features to use and discover. I recommend having a play around with the app to build up confidence; it shouldn’t take too long and is pretty fun as well.

Google Earth

Google Earth Pro

Google Earth Pro

Next we have aerial photographs. I use Google Earth Pro for investigating modern aerial photographs. Google Earth Pro is now available for free  and features additional tools that will allow you to measure, map and explore the 3D globe.

Best of all, Google Earth Pro features georeferenced 1940s aerial photographs; covering Kent, Suffolk, London and elsewhere; very handy for exploring Second World War military sites!

If you are new to Google Earth there are plenty of on-line tutorials that you can use to get up to speed with the program’s functions and features.

I will be covering how to interpret Second World War defences and identify features using 1940s aerial photographs in a future post; so watch this space!

Be aware that Google Earth doesn’t accept National Grid References. Apps such as the Grid Reference Finder will allow you to quickly search using UK National Grid references.

Libraries and Archives

Never underestimate your local library, archive or local studies library.

Sorry, I didn't have a picture of a library.

Sorry, I didn’t have a picture of a library.

Local libraries can be a great source of obscure or out of print local history books. Local history books often cover the Second World War; including eye-witness accounts and pictures of a local area during the period. As I’m sure you’ve guessed, you can use these to track down defences and other military sites in your area. I advise taking time to visit a number of local libraries to have a look for local history books that cover the period.

Archives contain large amounts of documents that pertain to your local area, it is also free to visit archives in your area, as long as you register. There is always the chance that your local archive service will hold documents that relate to local defence, Air Raid Precautions, Civil Defence or Home Guard activity. Newspaper articles, often held within the Archive, can also be used to build up a picture of activity in a given area during the war.

I recently stumbled upon an unpublished historical account in my local archive, which covered military activity in my village during the Second World War; including the activities of the local Home Guard. This account has helped me identify the general locations of three Searchlight Batteries, a Roadblock and an Army Camp; all of which remain to be recorded in the local Historic Environment Record (Don’t worry, I’m working on it!).

A visit to the Archive or Local Studies Library often proves fruitful and is a really good way of adding to your knowledge of local history.



The last source of information I will cover is books. There are a wide range of books covering Second World War defences, defence sites and the history behind their development.

Please be aware that some of these books are no longer in print and may be hard to come by or expensive.

Starting out

I recommend the following books if you are just starting out, would like to learn more about the different types of defences you may encounter and learn about their historical background.

British Home Defences 1940-45 (Fortress) by Bernard Lowry

ISBN 978-1-74176-767-3

This book offers a great introduction to British Home Defences of the Second World War, covering aspects such as Stop-Lines, The Home Guard, Coastal Defences and the defence of the air. If you are new to the subject, this a good read and will give you an insight into what you can discover.

Pillboxes and Tank Traps by Bernard Lowry

ISBN 978-0-74781-356-9

Another book by Bernard Lowry, this time covering Pillboxes and Anti-Tank defences. Featuring many pictures of pillboxes and defences during the war; the book covers the development and frequently changing strategy of defence chronologically; guiding you through the various stages of defence strategy. This is a must read for anyone who would like to learn more about pillboxes and Anti-Tank defences in the UK.

Through The Lens: British Anti-Invasion Defences 1940-1945 by Austin J. Ruddy

ISBN 1-901313-20-4

This was the first book I bought some 15 years ago. Although no longer in print, I recommend finding a copy. The book covers standard Pillbox types, Anti-Tank defences, Airfield defences, and pretty much all the defence site types that you would expect to encounter. What sets this book out is that it provides you with remaining examples (as of 2003) of each site type, as well as the National Grid reference for that site.

Specialist Books

The following books are of a more specialist nature, but certainly worth a look.

Pillboxes: A Study of U.K. Defences 1940 by Henry Wills

ISBN 0-436-5730-1

This is one of the first books that focussed on pillboxes. Be aware that this book is no longer in print and surviving copies can be expensive to obtain. However, if you do find a copy you won’t be disappointed.

Pillboxes of Britain and Ireland by Mike Osborne

ISBN 978-0-7524-4329-4

This book is essentially a detailed typology of all known pillbox types that can be found in Britain and Ireland. The book features an introduction covering the origins of the pillbox, along with examples and types that can be found around the world. This book features photographs and plans of many pillboxes in the UK and is a must for the serious Pillbox enthusiast or archaeology student.

Defending Britain: Twentieth-Century Military Structures in the Landscape by Mike Osborne

ISBN 0-7524-3134-X

Another of Mike Osborne’s works; this time covering 20th century coastal, inland, and anti-aircraft defences from the First World War, all the way through to the Cold War. Again, this book is very detailed but a must for anyone wanting a in-depth account of military defences in the UK.

Local Case Study books

These books cover specific areas of the UK; recommended if you are looking to learn more about your local defences, or would like to explore defences further afield.

The Defences of Worcestershire and the southern approaches to Birmingham in World War II by Mick Wilks

ISBN 9781904396802

I had the pleasure of meeting Mick at one of the Home Front Legacy training days in 2015. His knowledge of the defences in Worcestershire is unsurpassable and he’s also a very nice guy. This book represents the stellar work that Mick has conducted in the county and is itself unprecedented. Buy this book!

Silent Sentinels: The story of Norfolk’s fixed defences during the twentieth century by Christopher Bird

ISBN 9-780948-400810

A wonderful book that covers Norfolk’s many remaining Second World War defences. Also a great excuse to visit Norfolk.

The Battlefields that Nearly Were: Defended England 1940 & Defended England 1940: The South-West, Midlands and North by William Foot

ISBN978-0-7524-4328-7 & ISBN 978-0-7524-4786-5

Here are my favourites. These accounts cover the work of William Foot while undertaking English Heritage’s ‘The Defence Areas Project’. The book is written in a very engaging way and provides a fun, yet informative look at some of the country’s best surviving defence works.

A Guide to Second World War Archaeology in Suffolk by Robert Liddiard and David Sims

This series of 4 books cover all aspects of Second World War defence in Suffolk. The work undertaken by the authors, presented in these guides should act as an inspiration for all subsequent investigations and research projects. Although specific to Suffolk, they are a must.

20th Century Defences in Britain series by Mike Osborne and Alistair Graham Kerr

This series of books cover Norfolk, Suffolk, Cambridgeshire and elsewhere in detail. Well worth a look.


The only website you need to visit The Defence of East Sussex project website, run by Peter Hibbs. The work Peter has carried out is amazing. Take a look and get inspired!

The End!

So, that rounds off this blog, I hope you find it useful and enjoy exploring your local area.

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Starting Out by Chris Kolonko is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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Starting Out


It’s been a while since I have written anything (Over 10 months!). At the minute I find myself doing a lot of social media engagement and case study writing for work (Check out Home Front Legacy 1914-18!!!!); I rarely find the motivation to write my own ramblings when not at work. I have a lot of articles in the pipeline, which I may eventually get around to writing.

In an attempt to get myself writing again, I’ve put together a brief guide to starting your own research. This cover the sources of information available to anyone who would like to research and record Second World War military defences in the UK. The aim of this guide is to show you the sources of information you can consult via the wonder of the internet, as well as a number of other sources of information that are often overlooked.

Whether you are looking to learn more about Second World War sites in your area, or would like to conduct your own field work, research is key. Preliminary research, conducted before field work takes place is called a ‘Desk Based Assessment’ in the archaeology world.

If you do discover a site you would like to visit, ALWAYS gain landowner consent to do so before heading out. I am not responsible for any issues that arise as a result of using this research guide or visiting sites without express consent.

Starting Out-


It’s always best to start by outlining some basic objectives. These can be as basic as outlining what you are looking for and what you hope to achieve.

Are you looking to find sites in your local area? Are you hoping to learn more about the sites that survive in your area? Or, are you trying to identify a site you have discovered and would like to record it?

Once you are certain about what you would like to achieve then you can think about the sources of information you should consult. This will depend on the type of information you are looking for.

From experience I find focussing on a smaller area far more fruitful than trying to research and understand a larger area. It’s best to start small and work up to a bigger project.

Where can you start your research and find information?

The good news is there are a number of easily accessible resources that will allow you to get started. More importantly, you don’t need any previous experience to start your journey.

The Defence of Britain Project-

ADS Yorkshire

Your first stop should be the Defence of Britain project (DoBP) data. The Defence of Britain Project was conducted from 1995 to 2001 and set out to record, map and determine the condition of surviving 20th century military sites in the UK. The records created through this project ensured the re-discovery of many forgotten and important 20th century military sites. The information continues to be of great value to anyone interested in the Second World War and provides the basis for much research into the subject.

When the project ended in 2002 the project’s volunteers had recorded over 20,000 sites throughout the UK.

The data from the DoBP is available on-line, via the Archaeological Data Service, in the form of a searchable database, as well as a downloadable Google Earth overlay.

The Google Earth overlay allows you to view the locations and types of 20th century defence records throughout the UK and can be used to quickly discover sites in your local area. You will need Google Earth to open this file, but once you have downloaded the programme you will be able to view all the records easily.

Please be aware that some of the sites in the database may no longer exist due to demolition, coastal erosion or redevelopment. If you do find a site that has disappeared, you can help by reporting this to your local Historic Environment Record/Sites and Monuments Record to ensure they are aware.

You can check out these websites to find out more:

Archaeology Data Service DoBP archive– Find out more about the Defence of Britain project

DoBP search function– Search the Defence of Britain project database

DoBP overlay download– You will require Google Earth to open this file.

Extended Defence of Britain Overlay– this version of the DoBP overlay is updated by the Pillbox Study Group members and is well worth a look.

The Historic Environment Record and Sites and Monuments Record


Most counties have a Historic Environment Record/Sites and Monuments Record (HER/SMR). The HER is often maintained by the local council or other authority and holds information about historic and archaeological sites, listed buildings, designated or scheduled landscapes, and areas of historical importance. The information held by the HER is used to inform planning decisions and is open to members of the public conducting archaeological, historical, and genealogical research.

The HER is often overlooked but is a great source of information, especially when it comes to Second World War Sites.

You can search for HER records in your area via the Heritage Gateway website and find the contact details for your local HER/SMR with this useful list.

I advise that you contact your local HER for advice and guidance before going out and doing any field work and also ensure your findings, results or reports are provided to the HER for inclusion. You’re HER may also be able to advise you on how your information should be stored and presented for inclusion in the HER. As many Second World War sites are not protected, this is the only way remaining sites are to be preserved for the future.

Supporting your local HER is important!

For Scotland you can find your local HER via SMRForum  and Wales through the Archwilio website.

The National Record of the Historic Environment

The National Record of the Historic Environment, holds the archaeological and historic buildings records for sites throughout England.

Handily, the 420,000 records held can be searched online via the Pastscape website.

The Scottish and Welsh equivalents can be found at Canmore and Historic Wales

Historic England Aerial Photographs


Aerial photographs from the 1940s are key to identifying and interpreting Second World War military sites. 1940s aerial photographs are available from Historic England either by visiting their archives in Swindon or by requesting a free search of their collections.

The free search may reveal original 1940s RAF photographs of your area. These images are often oblique (taken from the side) or vertical (taken from above) and are a must for any serious site investigation. Copies of the photographs are available for a reasonable fee including simple photocopies, high resolution photocopies or high resolution digital copies; although pricey, I recommend the latter for serious site investigation.

You can find out more here via the Historic England website.

Although the majority of Historic England’s aerial photographs are not available to view online, over 95,000 of their oblique photographs are available for you to peruse via the web. The Britain from Above website allows you to view oblique photographs of the UK which sometimes catch First and Second World War sites. The location of some photographs is unknown, the Britain from Above website allows you to identify these unknown locations and ‘georeference’ them.

Find out more here- Britain from Above 

The End!

So, there you go. These sources should provide you with a good starting point for carrying out your own research. You may find something close to you, you may not. If you don’t find anything then don’t get disheartened. There are many other sources of information that you can tap into, more often than not in your local area; but that’s another story…

If you have any questions, then please feel free to drop me a message. And be sure to give me a follow on Twitter at @ckolonko.

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Starting Out by Chris Kolonko is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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Allotment Andersons

I thought I’d better make a quick blog post as its been a while. I got to spend my morning looking at Anderson shelters in a Sheffield allotment, with Drink Wise Age Well-Sheffield & LEAF Sheffield.


There are a total of two almost complete shelters and the remaining sections of at least two more!


We found the original makers marks still painted on the interior of one of the shelters and I even got to check if my Grandad’s Anderson Shelter spanner fitted the original bolts (which it did!)



I was also shown a post-war .303 bandoleer ammunition box that was used to store tools.


Overall a very good day. I’m looking into working with the two groups to record the shelters and look in further detail at the construction methods employed.

Mapping GHQ lines in Google Earth

Well, it’s been a while since I’ve posted a blog, this one has been in the planning stage for a while now following a prolonged period of ‘writer’s block’ and a very uncooperative brain. Without further ado here it is.

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Earlier this year I was forwarded a question via a colleague. The question I was posed related to the GHQ stop-line; the defence line planned by General Edmund ‘Tiny’ Ironside in June 1940, following his appointment as Commander-in-Chief of the Home Forces on the 17th of May 1940.

The GHQ line (or General Head Quarters stop-line) was to be the final line of defence running East from Bristol to the Thames Estuary then North to Edinburgh. This line was intended to protect the industrial heartland of the country had an invading German Army managed to breach the Coastal Crust defences, inland nodal points and secondary stop-lines. This defence line consisted of Infantry and Anti-tank pill-boxes, roadblocks, barbed wire entanglements, anti-tank obstacles and trench systems.

There’s some background for you, now back to the question.

As the question related to the length of the GHQ line and the route which it followed I decided to ascertain the length of the GHQ line had it been completed and the length of the GHQ line that was actually constructed between June and August 1940. Construction of the GHQ line having been slowed and eventually halted following the appointment of General Alan Brooke as Commander-in-Chief of the Home Forces on the 21st of July 1940. Ironside was subsequently retired and the defence strategy altered significantly, but that’s another story.

Initially I thought this was quite a straightforward question and I’d find the answer in one of the many books on the subject. I was wrong; although I could find plenty of information regarding the intended route of the GHQ line (although there were some distinct differences between sources and all maps were large scale), I could not find any information about the intended length of the line had it been completed.

I did however find a reference to the length of the GHQ line in Mike Osborne’s book ‘Defending Britain’ (Buy it!) which states that the section of GHQ line running from the Bristol Channel to the River Welland was approximately 400 miles in length. However, this only takes into account a short stretch of the proposed GHQ line and doesn’t include the GHQ East line that would have run from the River Welland up to Edinburgh. The book does describe the route of the GHQ line in some detail and this information came in handy.

So, although I knew the general route of the GHQ line, I still had a job on to tie down the exact route, trace it, and determine the length of the constructed and proposed GHQ lines.

I decided to work logically, finding and pinpointing the exact route of the GHQ line, I would then plot the information into my favourite tool, Google Earth, to show the route visually and to measure its length as accurately as possible given time constraints.

I consulted my copy Henry Will’s book ‘Pillboxes’ (get one if you can!), this has not one but many maps showing the GHQ line, including a copy of Ironside’s original map of divisional dispositions which shows the GHQ line, and 1:625 000 scale Ordnance Survey maps showing various lines of pill-boxes.

Comparing the maps in Will’s book with further examples I could find in other books showed there was a general consensus about the route of the GHQ line, with some slight variations, which allowed me to narrow down the area through which it ran. There was a slight problem though as most of the maps were large scale, making it hard to pinpoint the exact route in relation to nearby towns and cities.


A quick Google search will provide you with similar maps of the GHQ line (Note the differences).

With this information the next step was to see how it compared to the archaeological record.

The Defence of Britain project was conducted between 1995 and 2002. This project aimed to record the extant 20th century military sites in the UK. The project was a huge success and the results of this project have greatly improved our understanding of the 2nd World War defensive landscape.

The results of the Defence of Britain project have been converted into a Google Earth (Available here via the ADS website) which is very useful as I love Google Earth.

With the Defence of Britain data loaded into Google Earth it is very easy check the locations of the project results, trace stop-lines, and pick out features using modern aerial photography.


Defence of Britain project overlay in Google Earth with GHQ line visible

Looking at the distribution of pill-boxes in particular, one of the main defence types that formed the GHQ lines, it was possible to quickly discern numerous stop-lines within the UK. It was then simply a matter of using the maps and diagrams I had gathered to discern the GHQ line and follow the trail of records.

Using Google Earth’s ‘Path’ tool I simply followed the route of the various GHQ lines, picking them out in a nice Red colour.

GHQ Redline.jpg

Plotting a path in Google Earth following the River Brue

While plotting the GHQ line I did encounter a number of gaps, probably due to defences being demolished, un-recorded or not constructed at all. It was clear that the GHQ line followed many of the local rivers, canal systems and many natural or man-made obstacles (Such as railway embankments & high-ground) and I was aware that this was a strategy employed in siting the GHQ lines.

Henry Wills (1985) summarises the choice of topography- ‘The GHQ line followed natural and artificial waterways, using topographical features where possible, to create a continuous anti-tank obstacle’.

To fill in these gaps in the line it was just a matter of following the river, rail or canal network the GHQ line would have followed and plotting it that way. In some areas these features were not present, which suggests that either the GHQ line had followed an anti-tank ditch, or other feature that has since been removed, I had to make an educated guess using the large scale maps I had available. We will see later this proved quite effective!

After a very short time I had most of the Southern GHQ line plotted, running parallel to the South Coast, around London and then towards Cambridge. As the line nears Peterborough the line stops abruptly. I’ve come to the conclusion that this marks the progress of the GHQ line up to the appointment of General Brooke, who gradually halted construction of the GHQ line. Quite impressive for what was at most three months work!

GHQ constructed 2.jpg

Length of GHQ line constructed

The GHQ East line, which would have run from the Thames to the Humber Estuary and through Yorkshire on to Edinburgh, is largely non-existent and as a result hard to trace. The only way to trace this route was to utilise the maps I had found, especially Will’s OS maps, and follow the major rivers and canal networks. It took a while and some detective work but eventually  it was possible to map the most likely route of this stretch of GHQ line.

ADS Yorkshire.jpg

No visible GHQ line in Yorkshire

By applying a number of methods I eventually had the GHQ line mapped in its entirety, had it been finished. It was then a matter of adding up the lengths of the various ‘paths’ in Google Earth, mainly using a calculator as I am terrible at maths. After a few minutes of calculator bashing I was left with two figures, one for the length of the line constructed and one for the length of the completed GHQ line. Success!

The length of the Constructed GHQ line was approximately 466 miles, while the completed GHQ line would have been approximately 836 miles long (This includes the GHQ Green line around Bristol, the GHQ switch-line around Swindon, the Newhaven-Hoo line and a small switch-line near Stanhope that was illustrated on Henry Will’s map).

So long story short, after a lot of work I was able to provide an approximate figure for the length of the GHQ line (both built and proposed) based on the information and tools I had available. I also had an interactive and visual means of displaying the GHQ line, which was a bonus. I sent this information off to the recipient and everyone lived happily ever after.

But that’s not the end of the story…

There have been a number of unforeseen outcomes from this little project.

My colleague, who had originally forwarded me the question, sent me a picture of a crop mark they had found while looking at the GHQ overlay. It appeared to be an anti-tank ditch. I found the crop-mark using my GHQ overlay and switching to the 1945 Google Earth aerial photography (Unfortunately not available everywhere) did indeed find an anti-tank ditch. Much of the ditch had been in-filled but it was still plain to see. The Anti-tank ditch had thankfully been recorded through the Defence of Britain project.

GHQ AT ditch cropmark.jpg

GHQ line plotted in red with linear crop-mark to the left

Now here’s the good part: The ‘path’ I had placed in this area passed directly over the anti-tank ditch! As it would have been extremely time consuming to map the GHQ line meter by meter, in some areas I had had to trace the route from afar, using my better judgement and the concentrations of records in the Defence of Britain overlay as a guide. Quite by chance I had accurately followed a single anti-tank ditch that now survived only as a crop-mark. I was well chuffed with this result!

GHQ AT ditch cropmark2.jpg

1945 Aerial Photograph showing the extant Anti-Tank ditch

Closer inspection revealed the GHQ line’s reliance on natural and man-made obstacles was abundantly clear now. This highlights the importance of looking at the wider landscape when interpreting defences from this period as opposed to looking at the defensive remains in isolation.

Okay, so ‘where next?’ I hear you ask. Well my next step is to do some further research to check the accuracy of the GHQ line that I have plotted. While writing this blog post it has become clear that a stretch of the line in Cambridgeshire that I have plotted might be inaccurate. This is due to a number of converging stop-lines in this area which makes it difficult to discern the actual GHQ line. This should only take a matter of time but does highlight the issue of conflicting data.

I have continued mapping the Second World War defences in Google Earth, including the extant and proposed Coastal Crust defences and recently I’ve started mapping Secondary Stop Lines. So, watch this space!


Henry Wills (1985) Pillboxes: a study of UK defences, 1940, [London]: Leo Cooper in association with Secker and Warburg

Mike Osborne (2004) Defending Britain: Twentieth-Century military structures in the landscape, [Stroud] Tempus Publishing Ltd

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Mapping GHQ lines in Google Earth by Chris Kolonko is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.