Thoma is known for his indiscretion while a POW in the British captivity, when he unwittingly revealed the existence of the V-1 flying bomb and the V-2 weapons programmes. He was subject to surveillance by the British intelligence and while speaking to another German officer, was recorded discussing rockets that were being tested at Kummersdorf West, which he had observed while on a visit that also included "Generalfeldmarschall" Walther von Brauchitsch, the Commander-in-Chief of the Army. British reconnaissance flights over Peenemünde Army Research Center in May and June 1943 brought back unmistakable images of rockets at the facility; the subsequent bombing of the site severely disrupted the programme.