 Operation Freshman was the first British airborne operation conducted using gliders , its target was the Vemork Norsk Hydro chemical plant in Norway , which produced heavy water for Nazi Germany . By 1942 the German atomic weapons programme had come close to being able to develop a nuclear reactor , but in order for the reactor to function it would require a great deal of heavy water . The source of this water was the Norsk Hydro plant , which had been occupied in 1940 ; when the British government learned of the German nuclear developments , it was decided that a raid would be launched to destroy the plant and deny the Germans the heavy water . Several tactics were discussed and discarded as impractical , and it was finally decided that a small force from the 1st Airborne Division , comprising 30 sappers from the Royal Engineers , would land by glider a short distance from the plant , and demolish it with explosives . 
