Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation conducted using gliders, and its target was the Vemork Norsk Hydro chemical plant in Telemark county, 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 the heavy 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 required to develop a nuclear weapon.