It was operated by the Royal Air Force (RAF) from 1956 until 1984. Aircraft manufacturer A.V. Roe and Company (Avro) designed the Vulcan in response to Specification B.35/46. Of the three V bombers produced, the Vulcan was considered the most technically advanced and hence the riskiest option. Several reduced-scale aircraft, designated Avro 707, were produced to test and refine the delta wing design principles. The Vulcan B.1 was first delivered to the RAF in 1956; deliveries of the improved Vulcan B.2 started in 1960. The B.2 featured more powerful engines, a larger wing, an improved electrical system, electronic countermeasures (ECM) and many were modified to accept the Blue Steel missile. As a part of the V-force, the Vulcan was the backbone of the United Kingdom's airborne nuclear deterrent during much of the Cold War. Although the Vulcan was typically armed with nuclear weapons, it was capable of conventional bombing missions, a capability which was used in Operation Black Buck during the Falklands War between the United Kingdom and Argentina in 1982. The Vulcan had no defensive weaponry, initially relying upon high-speed high-altitude flight to evade interception. Electronic countermeasures were employed by the B.1 (designated B.1A) and B.2 from circa 1960. A change to low-level tactics was made in the mid-1960s. In the mid-1970s nine Vulcans were adapted for maritime radar reconnaissance operations, redesignated as B.2 (MRR). In the final years of service six Vulcans were converted to the K.2 tanker configuration for aerial refuelling. After retirement by the RAF, one example, B.2 XH558, named The Spirit of Great Britain, was restored for use in display flights and air shows, whilst two other B.2s, XL426 and XM655, have been kept in taxiable condition for ground runs and demonstrations. B.2 XH558 flew for the last time in October 2015, before also being kept in taxiable condition. A total of 134 production Vulcans were assembled at Woodford Aerodrome, 45 to the B.1 design and 89 were B.2 models, the last being delivered to the RAF in January 1965. For details of the development, design, operational history and variants, click here.