Observer Corps Post 1940

The Role of the Observer Corps (later Royal Observer Corps) in the Battle of Britain

Observers Corps Post - Crowborough, 1940. £431 (+p&p)
The role of the Observer Corps in the effectiveness of Fighter Command’s defence of Britain during the summer of 1940 was second to none. Yet, against the glamour of the fighter aircraft involved and the old schoolboy truism about radar having won the Battle of Britain, it is perhaps often overlooked in our remembrance of the Battle. I hoped to do my little bit towards redressing this balance by ensuring I included a suitable depiction of the Corps, carrying out their vital work tracking enemy aircraft, as part of my series of paintings of the events of the Hardest Day.

The Observer Corps 1940

Radar, and its brilliant exploitation by Fighter Command, were without doubt incredibly effective tools in giving early warning of raids. It is, however, an often overlooked fact that the relatively new Chain Home and Chain Home low radar systems of the time were only effective over the sea. Once raiders had passed over the British coastline, nearly all the tracking of hostile plots was dependent upon the Observer Corps. The aerial defence system of the UK was thus utterly dependent upon their work. This also provided the key information for the authorities to know in which areas to sound air raid warnings and all clears, at any given time, which, no doubt, saved many lives during the war.

Chain Home radar receiving masts, with a passing 17 Squadron Hurricane (detail from the painting "Back Among Friends")
Chain Home radar receiving masts, with a passing 17 Squadron Hurricane (detail from the painting "Back Among Friends")

The Observer Corps could trace its routes back to the First World War, when such units were first deployed to track the movements of Zepplin airship raids on Britain. Formally established in 1929, by 1940 it was under Dowding’s command as part of the air defence structure of the country. Key to its importance in the Battle was the way in which it had been integrated into a complex and effective system of monitoring and reporting hostile air activity, and scrambling fighter aircraft to respond quickly and appropriately to each threat.

"One Squadron Scramble" - Hurricanes of No. 1 Squadron. £460 (+p&p)
Hurricanes of No. 1 Squadron on a 'scramble'.

In recognition of the sterling and valuable work carried out by the Observer Corps during the Battle of Britain, King George VI granted it ‘Royal’ status and thus it became the ‘Royal Observer Corps’ from April 1941 onwards.

The organisation continued to serve with distinction in expanding roles throughout the war, whilst never neglecting its primary role of monitoring the skies over Britain for enemy aircraft. Briefly disbanded after the war, the Corps was reformed to serve in readiness for a fallout monitoring role in the event of a nuclear attack, throughout the Cold War, being finally disbanded in 1996.

Understanding the Form and Function of an Observer Corps Post in 1940

Finding a suitable composition for a painting which I felt could do any justice to the incredible task carried out by the Observer Corps during the Battle of Britain turned out to be no mean feat. The painting I finally came up with involved the portrayal of a real Observer Corps post location in Crowborough, East Sussex as the focus for the painting, with one of the real events of the Hardest Day unfolding in the sky behind. There is more detail on these events and how I arrived upon this composition towards the end of the article. Significantly though, there were no photos of the original 1940 post, which has long disappeared, so I set about studying and understanding a little more closely what the post might have looked like and what equipment was likely to have been in use there, so that I could recreate how it might have looked, as faithfully as possible.

This proved a really fascinating study and I have attempted to summarise the nature and role of a typical Corps Post of 1940 here, particularly to help in understanding the painting. I am particularly indebted to the website of The Time Chamber, for their excellent pictures of artefacts from Observer Corps Posts, together with an incredible amount of detail on the role and function of the Observer Corps throughout its history. I thoroughly recommend a visit to this site for anyone wishing to study the subject in detail. A list of other useful references is given at the end of the article.

At the outbreak of WW2, around 1000 Corps observation posts had already been set up. Posts were located at points with commanding visibility, for obvious reasons. The location of this post towards the top of the long south facing slope at Crowborough, with its beautiful view to the South Downs, is no exception. Some posts were built up to provide an elevated viewpoint and it seems that roof top sites were sometimes used too.

The view from the post in the painting, showing its elevated position.
The view from the post in the painting, showing its elevated position.

As an interesting aside, these should not be confused with the rooftop ‘watchers’ that were often posted, from amongst their own staff, by factories and other important installations on their own buildings. In these cases, these ‘watchers’ were to give out the alarm to the occupants of the building if aircraft were seen to be approaching the specific location involved, allowing the workers a minute or two warning of a raid which might hit the factory or installation itself. By using such watchers, many factories were able to continue valuable wartime work or production whilst air raid warnings were in place in the surrounding areas.

My own grandmother, who worked in the vital telephone exchanges during the war, remembered such arrangements. Indeed, she also told of being asked to fill in for one of these ‘watchers’ for a period and was handed a totally ordinary umbrella to take with her. It turned out (she recalled with her characteristic humour) that this was not because it was raining, but that it was the sole provision for her protection, while on the roof of the building, against anything that the Luftwaffe might drop out of the sky upon her!!

To return to the construction of an Observer Corps post; it seemed that there was no specific fixed design for such a post by this stage in the war. Rather, each local unit was allocated a shed for storage of equipment and given a budget of £5 to spend on materials and then left to construct the post using their own initiative. When we remember that many of the generation involved in this would have served in the trenches of WW1, this was perhaps not such a surprising or difficult task, the principles of field engineering will have been familiar to many at the time.

A detail showing the improvised construction of the post in the painting, showing its use of First World War style field engineering techniques.
A detail showing the improvised construction of the post in the painting, showing its use of First World War style field engineering techniques.

Typically, sandbags and corrugated iron seem to have been key components in most post constructions I have seen photos of, and I have tried to recreate this realistically and reflect the somewhat improvised nature of a typical post in the one that I have painted. Some posts seem to have had a ‘ring’ of what looks to be cement or concrete built around the top, which I have also added to the post here. I am not sure of the exact point of this, but as they seem to be very carefully laid flat and level, I can only imagine that this may have helped as a datum for providing a vertical angle when sighting aircraft (critical for estimating the aircraft’s position) in all directions.

The walls of the post were often marked with bearings or compass directions, and some posts seem to have had a series of four figure numbers posted around the walls. I assume these latter markings were grid squares for the map system in use by Fighter Command (but I cannot be certain of this). All such markings would have helped with the speed and accuracy of recording and reporting plots, an accuracy which was vital, as even a small error which failed to be spotted as it worked its way through the communications chain could mean the failure to intercept a raid or to alert the correct area to the imminence of an attack.

Typically, posts were manned by two Corps members, with a third where possible to assist with recording and relaying sightings. Prior to the war, the Corps was a voluntary, unpaid organisation. Once war broke out, members became paid on a full or part time basis. Remarkably, all posts were manned continuously 24/7 throughout the entire war, which is an astonishing achievement.

Each post was equipped with a field telephone. This was operated through a headset and chest mounted microphone, which would have left the operator’s hands free to continue sighting or other work. (The operator on the left of the painting can be seen wearing this equipment.) Using this, observations of enemy aircraft could be passed on to an Observer Corps control room. We have to remember too, in our current age of easy wireless communication, that the Corps’ communications were via field telephone lines, connected into the general telephone network, requiring wires (visible in the painting) to be laid to each post.

The field telephone in use, with its headphones and chest mounted speaking tube.
The field telephone in use, with its headphones and chest mounted speaking tube.

From the Observer Corps control room, plots from several posts would be cross referenced for verification and then passed on. Plots were used to alert relevant local authorities to put in place air raid alerts and to the Fighter Command Group HQ. Here a complex control system further filtered and assimilated all the incoming data and passed it around to Sector Controllers, who were responsible for scrambling aircraft to intercept the enemy. Information was also fed back to posts on likely enemy activity to watch out for in their area.

Despite what we would now consider to be the relatively ‘low tech’ of the system, it was remarkably efficient. Len Deighton, in his excellent book ‘Fighter’, states that the plots in the control rooms were rarely more than 4 minutes (equating to roughly 15 miles in aerial combat terms) behind events in the sky. For such a complex system, this is incredibly impressive and history has shown us that this was sufficient, and significant in tweaking ‘The Narrow Margin’. It allowed Dowding’s system within Fighter Command to constantly and dynamically place a numerically inferior defensive force of Hurricane and Spitfire fighters in the sky extremely effectively.

'Evening Fight' - Hurricane of F/Lt. Harry Raymond Hamilton, No. 85 Squadron.  £723 (+p&p)
Hurricanes of 85 Squadron on an intercept of a typical, numerically superior, raiding force.

One of the key technical features of the post was the ‘post instrument’. This was a piece of equipment that allowed an aircraft to be tracked through a sighting scope. The operator, having made an estimate of the aircraft’s height, was able to plot its position on the circular table map using the instrument, allowing a better estimation of location and direction to be obtained, than by mere visual assessment alone. A full explanation of its use is given with this Wikimedia Commons picture of a post instrument. This equipment can be seen in the middle of the painting. (In this case, it was not being used to track the visible aircraft, as the low pass of the departing Dornier would have been too fast and close for its use to be relevant.)

A close up of the post instrument, showing the sophisticated scope and plotting device, mounted on a map board.
A close up of the post instrument, showing the sophisticated scope and plotting device, mounted on a map board.

Binoculars and anti- glare sunglasses were also part of the standard issue equipment for the post and both would have assisted with allowing observers to see aircraft better for identification purposes. The Corps member on the right of the painting is holding a pair of the standard issue binoculars.

By mid 1940, the role of the Observer Corps in identifying aircraft types was becoming established, not having been envisaged as necessary in the original conception of their role, and would have been very useful in enhancing information on the composition of enemy formations first picked up by radar. One has to remember that these posts were also operational at night, and in cloudy weather with poor visual range. The Corps was then largely reliant on using sound to track and identify aircraft. Whilst this was less effective than visual sighting, it shows the remarkable skill, adaptability and determination of the Corps members to continue to provide as much useful information as possible at all times.

As the threat of invasion became very real in mid 1940, some posts were issued with firearms, usually a WW1 pattern rifle or two and a limited number of rounds, with officers being equipped with pistols. I am not sure whether the post at Crowborough had been issued with these, so I have not included them in the painting.

At the beginning of the war, there was no uniform for the Observer Corps, but members were provided with a red and white striped armband bearing the legend ‘Observer Corps’. From contemporary pictures, it seems as if the black beret was probably in use by this time too, so the personnel at this post are shown with these accoutrements. The issue of the first actual uniform, resembling a dark blue boiler suit, began around this time, so it might have been a plausible alternative interpretation to show the personnel dressed in these; in a nod to this I have put the right hand figure in a garment which could easily be one of these, perhaps just issued. Helmets were issued to Corps members too, though most photographs seem to depict them without. I imagine they may have hampered the ability to carry out tasks somewhat so they might often have only been donned where there seemed to be an imminent threat of danger.

The armband, which comprised the initial Corps uniform, is visible here, together with the late issue beret.
The armband, which comprised the initial Corps uniform, is visible here, together with the late issue beret.

The Combat Action Depicted in the Painting, 18th August 1940

Creating a painting which could do any justice in portraying the important role of the Corps and its tireless members was quite a challenge. I knew I wanted to tie the painting into the events of the 18th August 1940, although, in many ways, it could have been almost any day of the summer of 1940. On starting to think of possible compositions for the painting, quite a number of challenges became apparent. Firstly, I wanted the activity of the post to be clearly visually tied into the air battle above, but to retain the focus on the occupants of the post. Given the distance and height at which so many of the raiders were coming over, this would typically mean the aircraft would, at best, appear as tiny dots far up in the sky.

A possible exception to this seemed to be the daring, low level raid carried out by the 9th Staffel of KG 76 on Kenley airfield. This seemed a particularly relevant combat action which demonstrated the immense value of the Observer Corps. The nine Dornier Do.17 aircraft, of this elite, low flying Staffel, had flown in at virtually zero altitude, skimming the Channel water surface and then bobbing up and down over the treetops as they crossed Sussex and Surrey on their way to the target, with the intent of avoiding detection by radar or other means.

They were, however, sighted and reported into Fighter Command’s control system, firstly by a chance sighting by Royal Navy Patrol boats, but then they were subsequently tracked right the way across Sussex and Surrey by reports from the Observer Corps. This vital information allowed the RAF Sector Controllers to guess accurately guess their intended target and arrival time, and even this short notice allowed significant defensive measures to be ready against them by the time they arrived at Kenley.

The German plan had been for these raiders to arrive just after a high level attack on the airfield had been completed from a different direction. Due to errors in timing however, the low level attack of the 9th Staffel arrived over the target first, and so was met with the brunt of the defence action.

Coming in low and fast over the treetops at Kenley, they faced the full force of the airfield’s anti aircraft guns, as well as an innovative and rather terrifying rocket launched parachute and cable device, that effectively put a curtain of steel wires across their flight path. Furthermore, there were fifty Hurricanes and Spitfires that had been scrambled into the skies from Kenley, Croyden and Biggin Hill airfields, just in time to meet the arrival of both attacks.

'Stirring up the Hornets' Nest'- Hurricanes of 'Treble One', No. 111 Squadron. £723 (+p&p)
Hurricanes of 111 Squadron harry the departing raiders

The net result of this was summed up succinctly by Alfred Price in his book, the ‘Hardest Day’, where he tells that of the nine aircraft involved in the low level attack:

“...four were destroyed, two suffered serious damage and the remaining three suffered minor damage... It was a sombre case-history of what must be expected if low-flying aircraft have to meet alerted ground defences” -Alfred Price

Here, indeed, was a combat victory, which owed no small part to the role of the Observer Corps. It seemed too as if the low flying aircraft gave potential for an interesting painting, one which clearly tied the role of the Corps to the action going on above.

The Process of Creating the Painting of the Crowborough Post

The decision to go with this idea brought with it a new set of compositional problems for me. Firstly, a depiction of the nine Do17’s tearing low and unmolested across the Home Counties hardly seemed like a fitting way of depicting the success of the Observer Corps’ role. I was also faced with the difficulty of locating where any of the posts involved in the action might have been, to give a suitably accurate depiction of events. There seems to be very little easily accessible records on the locations of these posts in 1940, and whilst many of the post war bunkers are well documented, and quite possibly sited at the same locations as the earlier posts, I had no evidence of this as fact.

I did, however, manage to locate one description online, for the post at Crowborough Common, which gave me a very precise location for one post, citing the1940 post to have been:

"... just a few yards, perhaps no more than 30, to the north of the remaining, underground bunker.. of the post war post, at Crowborough on the golf course."

from: Crowborough Common, The Official Site

Studying the maps of the 9th Staffel’s movements that day, and the local topography, it seemed that Observers at the Crowborough post would have been unlikely to have spotted the attack as it came in. Interestingly, though, it seemed like it would have been almost directly on the estimated route by which the straggling and harried attackers made their departure.

This confluence of facts seemed to point towards a much more suitable composition: That of one of the departing damaged aircraft passing low over this Corps post on its return to France.

With a little more research, I was able to get a much clearer idea of what the landscape around this specific Observer Corps post looked like. Studying Price’s account a little more, I decided to depict the Do. 17 flown by Otto Stephani in the work, and I could begin to feel the bones of a painting emerging.

It was to show three members of the Corps watching as Stephani’s Dornier limped home overhead on one engine. It seemed like a way of marking the successful outcome of the Corps’ endeavours that day, and indeed throughout the Battle, whilst allowing me to express a dignified salute to the daring yet pyrrhic raid carried out by the 9th Staffel crews.

The damaged Dornier, piloted by Otto Stephani, limps home low over the trees.
The damaged Dornier, piloted by Otto Stephani, limps home low over the trees.

The focus of the painting was always going to be the Observer Corps post and I wanted to try and capture some of the details of a typical Corps observation post in the work. I feel depictions of the subject are really rather underrepresented in the overall artistic portrayal of the Battle and photos of such posts are also relatively few and far between. My research has found about 15 to 20 photos of such posts, some of which are not from the Battle of Britain period. There are also couple of excellent paintings of the subject, painted at the time. (link?)

Studying these resources made me realise the difficulty of the composition I had envisaged. To get across a sense of the whole of the post’s construction, and its setting within the landscape, would make it hard to capture any idea of what was going on inside it, as it seemed that its occupants could easily end up just being seen as heads over the parapet, if seen at all!

Most existing images depicting the inside of the post got around this by capturing the view down into the post, which worked well. This, however, if I adopted it, would leave little scope for capturing the aircraft in the sky, which now felt like an important element of my envisaged composition.

My resolution in the end was to pull the post almost right up to the viewer in the painting and elevate the viewpoint of it sufficiently to capture just a little of the inside of the post. This seemed to allow me to include a sense of the roles of the personnel in there, but without losing the landscape and aerial context of the painting. It seemed a rather challenging composition, but I felt that it might work.

I am pleased with the result. It is to my mind a ‘thoughtful’ rather than an overtly ‘dramatic’ painting, but in a way this seems entirely appropriate. The war of the Observer Corps was not the heightened cycle of mixed moments of adrenalin, fear, exhilaration and release that it was for their fighter pilot compatriots. I think it was rather, for the Observer Corps, a steady, stoic, and undaunted act of toil and patience. It must have been an act of faith to turn out day and night and contribute their unrelenting vigilance and calm, measured reporting. They were trusting, that in watching Britain’s skies continuously and unfailingly for the nation, they could make their own small, but significant contribution to the victory of a just cause and the defence of the last free corner of Europe.

The devoted personnel of the Corps. Each post was manned 24/7 throughout the war.
The devoted personnel of the Corps. Each post was manned 24/7 throughout the war.

It is unquestionable that their contribution was a decisive factor in the RAF’s victory of 1940.

It is my hope that this small and ‘thoughtful’ painting contributes in its own small way to helping us remember the invaluable role they played. I hope it helps stand to commemorate their remarkable, unflinching achievements in ensuring that throughout the Battle of Britain and indeed, the entire war, there could never be any question in the readiness of the nation’s defences, as per the Observer Corps motto: ‘Praemonitus Praemunitas’/ ‘Forewarned is Forearmed’.

Observers Corps Post - Crowborough, 1940. £431 (+p&p)


In addition to the links in the text, those interested in finding out more may find the following useful:

Military Histories British Air Defence page
Royal Observer Corps Museum
Wikipedia page on ROC
Imperial War Museum Observer Corps page


"Duel of Eagles" by Peter Townsend
"Fighter" by Len Deighton
"The Battle of Britain" by Kate Moore