way for waves of SAC bombers to follow. The plan was updated annually; as Soviet capabilities improved, more emphasis was placed on attacking airfields and missile bases. Nuclear testing . Special Valiant unit No. 1321 Flight was formed at RAF Wittering on 3 August 1954 which conducted ballistic test trials with Blue Danube practice bombs. It became C Flight of No. 138 Squadron in March 1956, and No. 49 Squadron on 1 May 1956. Valiants WZ366 and WZ367 were then flown to Maralinga, South Australia for Operation Buffalo. Valiant B.1 WZ366 of No. 49 Squadron became the first RAF aircraft to drop an operational atomic bomb when it performed a test drop of a down-rated 3-kt Blue Danube at Maralinga on 11 October 1956. The bomb landed about left and short of the target. The pilot was Squadron Leader Edwin Flavell, and the bomb aimer was Flight Lieutenant Eric Stacey, and both were awarded the Air Force Cross in the 1957 New Year Honours. On 15 May 1957, Valiant B.1 XD818 flown by Wing Commander Kenneth Hubbard dropped the first British hydrogen bomb over the Pacific, the "Short Granite", as part of Operation Grapple. No. 49 Squadron was selected to perform the live weapon drop and was equipped with specially modified Valiants to conform with the scientific requirements of the tests and other precautionary measures to protect against heat and radiation. The test was largely a failure, as the measured yield was less than a third of the maximum expected and the device failed to achieve a thermonuclear explosion as intended. The first British hydrogen bomb that detonated as planned was Grapple X Round A, dropped on 8 November 1957. The Grapple series of tests continued into 1958, and the Grapple Y bomb exploded in April 1958 with ten times the yield of the original "Short Granite". Testing was finally terminated in November 1958 when the British government decided to cease atmospheric testing. Project E As V bomber production picked up, the number of bombers exceeded the number of available British nuclear weapons. Britain had only ten nuclear bombs in 1955, and just 14 in 1956. To make up the difference, American nuclear weapons were obtained through Project E. Since they were in American custody, they were not available for the RAF to use as part of the UK's independent national nuclear deterrent; only British-owned weapons could be used for