On 4 November 1942, Thoma was captured by the British forces, and for the remainder of the war he was a prisoner in several senior officer prisoner-of-war camps in Great Britain, including Trent Park, Wilton Park, Grizedale Hall and Island Farm.
Following his indiscretion, further British reconnaissance flights over Peenemünde in May and June 1943 brought back unmistakable images of rockets at the facility which was developing guided missiles and long-range ballistic missiles better known as the V-1 flying bomb and the V-2.