No. 5 Group RAF effective squadrons of Bomber Command, personified by No 617 Squadron the "Dambusters", formed from 5 Group aircrew in March 1943. Most of the group's main airfields were around Lincoln, including RAF Scampton. By the end of the war the group had grown to 15 squadrons. The group was noted for its high accuracy bombing, being involved the sinking of the "Tirpitz" in November 1944 and the shattering of the strategic Bielefeld railway viaduct in March 1945. The Group introduced new weapons operationally, including Barnes Wallis's "bouncing" and his Tallboy and Grand Slam "earthquake" bombs. The group was disbanded on 15
No. 617 Squadron RAF Club the Interim Megaton Weapon, Yellow Sun Mk.1 and certainly Yellow Sun Mk2. American bombs were also supplied to the RAF V-bombers for a short period under the Project E arrangements.The Squadron began almost immediately to upgrade yet again to the Vulcan B2, taking delivery of the first on 1 September 1961, although its high-level strategic bombing role remained unchanged until the advent of effective Soviet Surface-to-Air Missiles forced Bomber Command to reassign V-bombers from high-altitude operations to low-level penetration operations in March 1963, when the Squadron's Vulcans adopted a mission profile that included a 'pop-up' manoeuvre from 500–1,000 ft