- Based at RAF Leeming, 609 (West Riding) Squadron consists mainly of RAF Regiment gunners.
- Formed at Yeadon in 1936 and flew Spitfires during the Battle of Britain.
- The only RAF Regiment Reserve unit in the north of England.
- Supports 2 Force Protection Wing.
1936 - Formed at Yeadon as a bomber squadron, and converted to fighters in 1938.
1939-1945- The unit achieved a particularly distinguished record in the Second World War. It was the first Spitfire squadron to achieve 100 air-to-air ‘kills’. Later in the war 609 Squadron pioneered the use of the Hawker Typhoon in the ground-attack role.
1945-57 - After the war, 609 Squadron converted to the Gloster Meteor jet fighter. The squadron was disbanded in 1957.
1998 - The Air Defence Support Squadron (ADSS) was formed, a multi-traded reserve unit in the Air Defence Role to support the Tornado F3 Wing based at RAF Leeming. In 1999 the ADSS became an Operational Support Squadron (OSS) and was granted the number 609.