It was only by chance that a passing Norwegian trawler spotted the haggard men dressed in ski gear in September 1945, four months after the end of the conflict in Europe.

The surprised rescuers then saw the leader of the group take out his pistol and hand it over.

``It was the last German surrender of the war,'' said Eckert Dege, the son of the German commander.

The BBC pieced together the story of the group and their little-known war from military archives and accounts from German war veterans.

Deployed under the code name `Hagen', the soldiers were one of a series of crack teams sent in turns to the Norwegian-owned island to collect weather information. They landed by submarine in September 1944.

``They were recruited from all branches ofthe German armed forces and aged between 18 and 22, except for the wireless operator and my father who was the unit commander,'' Dege said.

He added that ``the importance and hardship of the job meant that they ranked higher than U-boat crews -- and they were the elite of the elite''.

The data they gathered were sent directly to the headquarters of the German airforce, the Luftwaffe, in Berlin and used for air and sea attacks by the German forces.

But after the armistice, the ultra-secret nature of their mission meant the men were forgotten, with no orders for what to do next and no means to leave the island.

Living on their food rations, they nevertheless managed to keep recording the weather before finally being picked up by the trawler.