Following World War II, Great Britain sought strategic bombers with long range, heavy bomb loads, high speed, high-altitude performance, and worldwide basing flexibility, leading Vickers, Avro, and Handley Page to develop the Royal Air Force’s Valiant, Vulcan, and Victor. Avro chose a delta-wing design for its Model 698, and because reliable transonic aerodynamic data on delta wings was lacking, it created the 707 research vehicle, from which emerged the Vulcan B.1 with a broad delta wing and circular-cross-section fuselage. Early flights showed that high-G maneuvers at altitude caused heavy buffeting and wing fatigue, so the wing was modified with varying sweep along the semi-span, producing the distinctive kinked-delta shape. The aircraft had a vertical tail, elevators integrated into the delta wing, four engines in the wing root, and a fuselage blended into the wing with space for two pilots, three aft-facing crew members, and one internal bomb bay for bombs or mines. As the B.1 entered service as a high-level bomber, Avro developed the improved B.2 with an enlarged wing, revised control surfaces, in-flight refueling capability, and a lengthened fuselage, and it was designed to carry the Blue Steel stand-off bomb or the Skybolt ballistic missile. After Skybolt was canceled and Polaris was adopted instead of Blue Steel, the Vulcan B.2 was reevaluated and adapted from a high-level nuclear role into a low-level conventional bomber carrying general-purpose bombs and advanced electronic countermeasures, while several B.2s were later modified for reconnaissance as the SR.2. The B.2 and SR.2 remained in service into the 1980s and were retired shortly after service in the Falklands War.