Stradishall – Manhay/Grandmenil, Belgium
This sortie to Belgium drops Jean Lamy, code-named ‘Dewar’, a wireless operator for the ‘Clarence’ circuit.
Whitley P5029 takes off from Stradishall at 20.15 on the 12th. An hour-and-a-half later 3 Group phones to ask Stradishall about the endurance of that particular Whitley ‘X’, and is given the answer “12 hours”. The query is unlikely to have had anything to do with that night’s operation to Belgium, which was well within this Whitley’s endurance. More likely it is related to the plans for a re-run of ADOLPHUS to Poland, or perhaps another long-distance operation. By this time Oettle and Keast are over the North Sea and can’t answer for themselves.
In any case the answer is wrong: P5029 has no additional fuel tanks, which limits its operational radius, though they can be fitted. Operations to Norway or Denmark are possible, but only by setting off from the east coast of Scotland or Yorkshire. Twelve hours would be a generous estimate for a Whitley equipped with the full complement of six additional fuel tanks; the maximum recorded length of a Special Duties Whitley sortie fitted with these tanks is still less than eleven hours.
Lamy is dropped near Manhay, in the Ardennes region, a land of rich farmland valleys closely bordered by wooded hills. P5029 lands at Honington at 00.40 on the 13th after a four-hour trip. Keast records the sortie as flown on the 13th, but Stradishall confirms the sortie as taking place on the night of the 12th-13th.
Lamy sends his first message from Grandmenil, the next hamlet along. According to Emmanuel Debruyne, Lamy makes around 120 transmissions from his parents’ home, his speed and confidence increasing, as does the amount of intelligence he gets back to London. But the Abwehr is developing its own skills, in radio triangulation techniques, so Lamy’s luck is never going to last. On 26 March he is arrested at his set. According to Etienne Verhoeyen he succeeds in short-circuiting his set before the Germans arrive, but his codes and a series of coded messages fall into German hands. Under the threat of reprisals against his family, which knows Walter Dewé and other senior figures in the Belgian intelligence service, Lamy allows himself to transmit under German control. Within three months, overconfidence and a training failure to instil strict W/T discipline in these agents have led to the eradication of two circuits (‘Williams’ and ‘Martiny-Daumerie’), and ‘Clarence’ is rendered impotent.