This is one of only 50 covers signed by Billie Stephens. Billie Stephens became one of the few Naval officers to escape from Colditz when in October 1942 he and two fellow officers escaped via a cellar connected to the far side of the camp. It took over eight hours to make their way out of the camp, and then a further four days to reach the safety of Switzerland.
The cover is also signed by Lieutenant Mike Scott of the Durham Light Infantry who was captured in May 1940.
Mike Scott was one of 65 officers who escaped from Oflag VIIB, at Eichstätt in Bavaria through a tunnel in June 1943. Plans for a mass breakout had begun in 1942 shortly after the arrival of two British officers, Lieutenant Jock Hamilton-Baillie (known as HB) and Captain Frank Weldon. They had been involved in an escape from their previous camp at Warburg. The plan at Eichstätt was to dig a tunnel starting from under a latrine, passing under a rocky slope and up to a villager's chicken coop about 30 metres away. Tunnelling was difficult because of the rocky ground being excavated. However, the obvious difficulty of digging this terrain also meant that the Germans did not search this area of the camp for possible tunnels. Instead, they focussed their investigations on the other side of the camp, where they had discovered soil deposited by the tunnellers. 
The tunnel was completed by May and the break out took place on the night of 3-4 June. By dawn, 65 POWs were out. Travelling either in pairs or small groups, most headed for neutral Switzerland, but eventually all were recaptured. After two weeks held in detention, all 65 men were sent to Colditz. Their time on the run had occupied over 50,000 German police, soldiers, home guard and Hitler Youth for a week. 
This is an extremely rare cover in excellent condition.