Only complete Valiant out of 107 built that survives at RAF Museum Cosford,which also has on display a Victor and a Vulcan. This triad of V-bombers formed Britain's airborne nuclear deterrent. A Valiant test dropped Britain's first A-bomb in 1956. XD818 from No. 49 Sqn. dropped Britain's first live H-bomb in 1957 during Op. Grapple. It was converted to a tanker in 1961. By Dec. 1964,all Valiants were grounded due to metal fatigue and withdrawn in 1965.