Chevaline was a system to improve the penetrability of the warheads used by the British Polaris nuclear weapons system. Devised as an answer to the improved Soviet anti-ballistic missile defences around Moscow, the system increased the probability that at least one warhead would penetrate Moscow's anti-ballistic missile (ABM) defences, something which the Royal Navy's earlier UGM-27 Polaris re-entry vehicles (RVs) were thought to be unlikely to do.
Chevaline at RAF Cosford
A British Polaris missile at the Imperial War Museum, London
Polaris (UK nuclear programme)
The United Kingdom's Polaris programme, officially named the British Naval Ballistic Missile System, provided its first submarine-based nuclear weapons system. Polaris was in service from 1968 to 1996.
A Polaris missile is fired from the submerged ballistic missile submarine HMS Revenge
Admiral Arleigh Burke, the US Navy's Chief of Naval Operations from 1955 to 1961
Admiral of the Fleet Lord Mountbatten, the First Sea Lord from 1955 to 1959, and the Chief of the Defence Staff from 1959 to 1965
President John F. Kennedy (left) meets with the Prime Minister of the United Kingdom, Harold Macmillan (right), at Government House in Hamilton, Bermuda, on 22 December 1961.