RAF Cranwell was opened in April 1916, during the First World War, as an RN aeroplane, airship and balloon training station, under the Admiralty, and known as HMS Daedalus. It became so large that it was split into two, known as the South and North camps. It survived the post-war defence cuts to become the home of the RAF Cadet College and School of Technical Training. It was renamed the RAF College in 1929 and the present buildings were erected soon afterwards, being formally opened by the Prince of Wales in 1934. Cranwell was now at the very heart of the RAF and its airfield was used to launch many of the RAF's long distance record-breaking flights of the 1930s. On the day that the Second World War was declared in 1939, it was closed and reopened again as the RAF College Service Flying Training School in 1939. By 1941 it was also a training school for Radio and Signals Operators. The hospital which had been there since 1922 was moved to Rauceby hospital. {1}{2} Aircraft obstructions are visible on aerial photographs. {3} The College Hall and several other buildings are listed. See PRNs 64321-5. {4} A railway branch line, opened in 1916, connected the base with Sleaford. It closed to passengers in 1927 and completely in 1956. The former station building is now in use as a guardhouse. {5}