The Vickers-Armstrongs Valiant is a British quadjet high-altitude bomber, and was part of the Royal Air Force’s V bomber nuclear force in the 1950s and 1960s. The Valiant was the first of the V bombers to become operational, and was followed by the Handley Page Victor and the Avro Vulcan, which were more advanced. The Valiant has the distinction of being the only V bomber to have dropped live nuclear weapons. Valiant was least successful of the 3 V-bombers. It had some structural airframe problems and was phased out years before the Vulcan and the Victor.