American military forces were first stationed at High Wycombe in 1942, shortly after the United States' formal entrance into the Second World War. So urgent was the action that Wycombe Abbey School, situated on the land that would become the station, was given three weeks to find new facilities; failure in this effort led to the school's closing, until the independent girls' school was returned by the US in 1945. An underground bunker, which later became a nuclear-reinforced bunker was built within the grounds of the school and was codenamed "Pinetree".