No. 5 Group was a Royal Air Force bomber group of the Second World War, led during the latter part (February 1943 – 1945) by AVM Sir Ralph Cochrane. History Overview The Group was formed on 1 September 1937, with its headquarters at RAF Mildenhall, in Suffolk. In October the same year, the group headquarters (HQ) was moved to St Vincents Hall in Grantham, Lincolnshire. During the Second World War, 5 Group was concentrated primarily in south Lincolnshire (whereas 1 Group was more concentrated in the north of the county). Most of the 5 Group airfields were around Lincoln, including RAF Scampton. By the end of the Second World War, the Group had grown to 15 squadrons. During the war, it included a significant proportion of Royal Australian Air Force (or Australian-born RAF) personnel, both aircrews and ground staff, who were concentrated in three "Article XV squadrons": No. 455 Squadron RAAF, No. 463 Squadron RAAF and No. 467 Squadron RAAF. The Group also famously included an elite, multi-national unit: No. 617 Squadron, perhaps better known as "The Dambusters". 617 Sqn was formed in March 1943, and comprised RAF, RAAF, RCAF/Canadian and RNZAF/New Zealand aircrew personnel, who had been hand-picked from squadrons throughout Bomber Command. Led by 617 Squadron, the Group often engaged in special missions, using new weapons, such as Barnes Wallis's bouncing bombs, and two type of "earthquake bomb": Tallboy and Grand Slam. 1939 – 1945 From 11 September 1939 until 22 November 1940, Air Vice Marshal (AVM) Arthur Harris was in charge. The group started the war with 10 squadrons, all equipped with the Handley Page Hampden. The Group continued to fly only Hampdens until the northern winter of 1940–1941 when it began to convert to the new Avro Manchester. Early in 1942, the Manchester, was replaced by its four-engined variant: the Avro Lancaster, started to equip the group squadrons. On 17 October 1942, under Operation Robinson, some 86 Lancasters from 5 Group (without fighter escort) flew deep into occupied France to attack the Schneider armaments works at Le Creusot and the associated electrical station at Montchanin. On the night of 22–23 October, 85 Lancasters of the Group attacked Genoa without a single loss. On 24 October, 74 Lancasters delivered a daylight attack on Milan. In May 1943, 617 Squadron breached two of the Ruhr dams during the famous "Dams Raid": Operation Chastise. AVM Ralph Cochrane, who was