The Merchant Ship Fighter Unit (MSFU) was a Royal Air Force operational aircraft unit based at RAF Speke, in south Liverpool, now Liverpool John Lennon Airport during World War II. The role of the MSFU was to provide pilots, crews, support personnel and aircraft to operate from 35 merchant ships outfitted with a catapult on the bow, referred to as Catapult Aircraft Merchant ships, a stop-gap initiative to provide air support to convoys out of reach of land in the early part of the war when aircraft carriers were scarce. The aircraft operated by the MSFU were converted Mk1 Hawker Hurricanes that were near the end of their useful lives and were often Battle of Britain veterans. The alterations included catapult fixing points and the addition of a naval radio. The MSFU was formed at Speke on 5 May 1941 and provided detachments to the CAM ships, each vessel being equipped with one Sea Hurricane plus an RAF pilot and support crew.