 Fairey Battle light bombers were used as training aircraft to convert pilots from the fixed undercarriage biplane Hinds to much more modern monoplane Spitfire with its retractable undercarriage.At the outbreak of war, the squadron was called up to full-time service and initially served on defensive duties in the North of England.In May 1940, the squadron moved to RAF Northolt and flew over the Battle of Dunkirk during Operation Dynamo.