In early planning against the outbreak of war the Government indicated a wish to use Mardon Hall as a hospital, but it continued as student accommodation until 1943, when it was taken over by the American Red Cross as a rest centre and Psychological Hospital for American troops. A wartime German map, held by the Devon Record Office, has the adjacent Reed Hall and the University's Washington Singer Laboratories marked as military targets, but not Mardon. The Hall was returned to student use in 1945.