The RAF Advanced Air Striking Force (AASF) comprised the light bombers of 1 Group RAF Bomber Command, which took part in the Battle of France during the Second World War. Before hostilities began, it had been agreed between the United Kingdom and France that in case of war, the short-range aircraft of Bomber Command would move to French airfields to operate against targets in Nazi Germany. The AASF was formed on 24 August 1939 from the ten squadrons of Fairey Battle light bombers of 1 Group under the command of Air Vice-Marshal Patrick Playfair and was dispatched to airfields in the Rheims area on 2 September 1939. The AASF was answerable to the Air Ministry and independent of the British Expeditionary Force. For unity of command, the AASF and the Air Component of the BEF (Air Vice-Marshal Charles Blount), came under the command of British Air Forces in France (Air Vice-Marshal Arthur Barratt) on 15 January 1940. Using the bombers for attacks on strategic targets in Germany was set aside due to Anglo-French reluctance to provoke German retaliation and attacks on German military forces and their communications were substituted. The Battle of France began with the German invasion of the Low Countries on 10 May 1940. The Battle squadrons suffered 40 per cent losses on 10 May, 100 per cent on 11 May and 63 per cent on 12 May. In 48 hours the number of operational AASF bombers fell from 135 to 72. On 14 May the AASF made a maximum effort, 63 Battles and eight Bristol Blenheims attacked targets near Sedan. More than half the bombers were lost, bringing AASF losses to 75 per cent. The remaining bombers began to operate at night and periodically by day, sometimes with fighter escorts. From 10 May to the end of the month, the AASF lost 119 Battle crews killed and 100 aircraft. Experience, better tactics and periods of bad weather from 15 May to 5 June led to losses of 0.5 per cent, albeit with a similar reduction in effectiveness. On 14 June, the remaining Battles returned to Britain; the Hurricane squadrons returned on 18 June and rejoined Fighter Command. The AASF was dissolved on 26 June, the Battles returning to 1 Group, Bomber Command, to prepare for operations against a German invasion, along with the rest of the Royal Air Force. Background 1930s Anglo-French air policy Once British rearmament