RAF Medmenham, the photographic intelligence centre that provided Britain and its allies with detailed information on enemy activities across Europe and the Mediterranean in the 1940s, enabled the RAF to plan and assess missions based on the best intelligence. The vital role it played in the Allied war effort is little-known even today.
In 1941 Danesfield House near Marlow in Buckinghamshire became home to RAF Medmenham. The Central Interpretation Unit (CIU) was established there after bomb damage, and a lack of space to house the expanding unit forced their relocation from Wembley. However, even the expansive Danesfield House became too small as the workforce grew from 231 to more than 1,700. Soon, huts like those used at Bletchley Park were constructed to house many of the CIU sections.In the build up to D-Day and beyond, almost 1,500 intelligence reports and 600,000 prints were being produced every month. This was photographic intelligence production on an industrial scale, and was made possible by the organisation of Medmenham into 20 photographic intelligence sections with 15 intelligence support sections. Medmenham’s Photographic Interpreters, or PIs as they were known, worked with basic stereoscopes. These presented offset images separately to the viewer’s left and right eye, which the brain would unconsciously combine to give the illusion of three-dimensional depth. This allowed PIs to extract far more detail from the images than was possible with a single two dimensional photograph.Many of the photographs were taken by hand-picked pilots in camera-equipped Spitfires and Mosquitos. To accommodate the numerous cameras and increase their speed, Spitfires would also have their guns removed. Although lacking in weapons, it was believed by Wing Commander William Tuttle of the Photographic Reconnaissance Unit that speed would be their armour, stating: “You don’t need guns when you’re flying the fastest planes in the sky.” In addition to the images obtained via dedicated reconnaissance missions, cameras were also fitted to Bomber Command aircraft. This was to provide photographs for bomb damage assessment back at Medmenham. Bomber Command cameras had a delay timer which started when the bombs were released, and calibrated to take shots around the time the bombs detonated, capturing images of their impact. The army of specialists at Medmenham were capable of analysing the thousands of photographs that arrived daily, and producing fully illustrated, detailed analytical reports as well as diagrams and models. Headed by Wing Commander Douglas Kendall, RAF Medmenham had many successes during the Second World War. In September 1940 it correctly identified the rapid German build-up of invasion forces and barges at the channel ports, then the gradual winding down of these forces from October to December.Medmenham’s analysis of Bomber Command missions also proved to be vital, though its findings were not always well received. In 1940 and 1941, it pointed out how often targets were missed, sometimes by many miles, as they tracked the fall of bombs on the reconnaissance photographs.
The section dedicated to assessing bomb damage – K Section – was also able to show that targets reported as being hit many times had in reality received no hits at all. As technological aids to navigation and bombing such as Gee and Oboe were implemented, Medmenham was able to provide photographic evidence of Bomber Command’s improved accuracy.In 1942 Bomber Command organised its first 1,000 bomber raid. Known as Operation Millennium, the target was the German city of Cologne. The very next day Medmenham produced a report on the raid. This was followed a few days later by a far more detailed report, complete with an annotated mosaic image of the city showing the true extent of the damage, and listing in detail exactly what had been destroyed. K Section at Medmenham produced reports for Bomber Command on almost every bombing mission undertaken during the war; all of which survive and are held in the National Archives at Kew.
As well as reporting on post-operational damage, Medmenham also provided extensive intelligence on targets in advance of operations. Operation Chastise (known more famously as the Dambusters raid) was one of the most iconic RAF missions during the war. It involved the bombing of the Möhne and Eder dams by 617 Squadron. In the build up, Medmenham provided intelligence reports, photographs and models of the dams to aid planning. It was essential to the success of the operation to know the water levels to within a couple of feet and any anti-aircraft defences protecting the dams, and these reports were the only way Barnes Wallis and the planners could gain that information.Medmenham also prepared thousands of intelligence reports and millions of photographs to support D-Day. They monitored the railways around Normandy daily in the build-up to D-Day and afterwards to ensure that the Allies were keeping the region inaccessible by rail, and thereby delaying vital German reinforcements.
Some of the most secret and successful, work done by Medmenham was L Section’s identification of the German V Weapons programme. This section studied aircraft industries and new types of aircraft, and was commanded by Flight Officer Constance Babington Smith. A journalist on The Aeroplane magazine before the war, Babington Smith’s knowledge of aircraft led her to volunteer for the WAAF. While studying photographs in 1943 she spotted scorch marks on the runway grass at Peenemünde in Germany, showing that the Germans had developed a twin-engine jet. Later that year she also noticed a rocket-like object at the same site – making her the first person to identify a V1 ‘Doodlebug’. This discovery resulted in a special team being created to further study the V Weapons programme. Between late 1943 and early 1944 this team, known as Crossbow, successfully identified all V1 heavy launch sites.In addition to Constance Babington Smith, many other women served at RAF Medmenham, often in roles vital to the Allied intelligence effort. Sarah Oliver, the daughter of Winston Churchill, was posted to Medmenham where she worked as a plotter of photographic reconnaissance sorties. Her hard work soon saw her commissioned and trained as a Photographic Interpreter. She was well-liked among her colleagues due to her diligence and the fact that she never pulled rank, despite her father being Prime Minister. Another example of the exceptional talent Medmenham boasted during the war was Dorothy Garrod. Having read history at Newnham College Cambridge before training as an archaeologist, Garrod became the first female professor at either Oxford or Cambridge when she was appointed Disney Professor of Archaeology at Cambridge in 1939 – nine years before Cambridge awarded degrees to women. Garrod volunteered for the WAAF and was posted to RAF Medmenham as a PI because of her archaeological knowledge. She proved to be exceptionally talented, using her analytical mind and eye for detail in the secret Combined Operations Section. Garrod would often be found at her stereoscope, scouring desert landscapes for signs of Axis activity in the run up to Operation Torch, the Allied campaign in North Africa.
RAF Medmenham continued to provide strategic photographic intelligence support to the end of the war and beyond. Indeed, at the close of hostilities Douglas Kendall even travelled to Germany to rescue German reconnaissance photography. This included substantial coverage of the Soviet Union, which proved vital to the UK and USA until the arrival of U2 and satellite reconnaissance in the late 1950s and early 1960.The Medmenham Collection covers the history of military aerial photographic interpretation and imagery analysis from its beginnings, through both world wars to the present day. A museum display on RAF Medmenham can be found at the Defence Intelligence and Security Centre’s Military Intelligence Museum at Chicksands, south of Bedford, and the Medmenham archive is located at Wyton, just east of Huntingdon. Both the museum and the archive owe their existence to the enthusiasm of Medmenham Association members.Paul Stewart served for 35 years in the RAF with tours in tactical and strategic photographic interpretation, where he developed a healthy respect for the Photographic Interpreters from RAF Medmenham. After retiring from the RAF, he completed a PhD on the work of Medmenham during the Second World War. He is also Chairman of The Medmenham Association – an association for former and current Photographic Interpretors and Image Analysts.
This feature first appeared in Air Mail, the RAF Association members’ magazine. Non-members can receive Air Mail, plus other membership benefits, by signing up here.
All images copyright of Medmenham Association.