Royal Air Force Boulmer or RAF Boulmer is a Royal Air Force station near Alnwick in Northumberland, England, and is home to Aerospace Surveillance and Control System (ASACS) Force Command, Control and Reporting Centre (CRC) Boulmer. The School of Aerospace Battle Management and support staff was based there until 26 July 2019; it has since moved to RAF Shawbury. Until 30 September 2015, it was also home to A Flight, No. 202 Squadron RAF, who flew the Westland Sea King HAR.3 in the SAR (Search and Rescue) role. History Second World War In 1940 a decoy airfield was set up near the village of Boulmer to divert German attacks from nearby Royal Air Force (RAF) airfields such as RAF Acklington. As the air threat to the United Kingdom receded, the decoy airfield, with its grass runways and plywood and canvas Hurricanes, was abandoned. In March 1943 RAF Boulmer was reopened as a satellite airfield to house the advanced flights of No. 57 Operational Training Unit RAF (a Supermarine Spitfire training unit based at RAF Eshott, Boulmer's parent unit). Part of the airfield formed the basis of a caravan site with the runway and taxiway being used as an access road to the site. The site remains and is called Seaton Park. Cold War By 1950, the threat of the atomic bomb had caused a serious rethink in the organisation of air defence and a plan, codenamed ROTOR, was brought in to replace many of the existing stations with new protected underground operations rooms. The site chosen for one of these new underground Ground-controlled interception (GCI) stations was close to the former RAF Boulmer which had been returned to agriculture at the end of the Second World War. The station was to have a two-level underground operations room designated as an R3. The R3 was never intended to survive a direct hit from a nuclear weapon but was designed to withstand a near miss from Russian bombing with 2,200 lb armour-piercing high explosive bombs dropped from 35,000 feet. A target date for completion of the station was set as 21 August 1953 and although not complete, the station opened on time with limited capabilities using an American AN/FPS3 long-range search radar and an AN/TPS10 height finder. The station became known as 500 Signals Unit under the control of RAF Acklington and part of 13 Group - the station motto 'Semper in