UK Polaris programme

The United Kingdom's Polaris programme provided the first submarine-based British nuclear weapons system.

"Polaris" itself was an operational system of four Resolution-class submarines, each armed with 16 UGM-27 Polaris A-3 ballistic missiles, with each missile able to deliver three ET.317 thermonuclear warheads around a single target. This configuration was later upgraded to carry two hardened warheads along with a range of decoys.

Operated by the Royal Navy and based at Clyde Naval Base on Scotland's west coast, a few miles from Glasgow Scotland's largest city and the UK's third largest city. At least one submarine was always on patrol to provide a continuous at-sea deterrent.

The British Polaris programme was announced in December 1962 following the Nassau Agreement between the US and the UK. Construction of the submarines began in 1964, and the first patrol took place in June 1968.

In the 1970s it was determined that the re-entry vehicles were vulnerable to a Soviet anti-ballistic missile screen concentrated around Moscow. To ensure that a credible and independent nuclear deterrent was maintained, the UK developed an improved front-end named Chevaline. There was huge controversy when this project became public knowledge in 1980, as it had been kept secret by four successive governments while incurring huge expenditure.

Polaris patrols continued until May 1996, by which time the phased handover to the replacement Trident system had been completed.

The Royal Navy began seeking a role in the United Kingdom's nuclear weapons program after World War II. In 1948 it proposed carrier-based aircraft for nuclear weapons delivery, although bombs small enough to be carried on such craft did not yet exist. Its "carriers versus bombers" debate with the Royal Air Force for funding and support resembled the similar interservice dispute in the United States at this time that led to the "Revolt of the Admirals". In 1956 Britain began participating in United States Navy admiral Hyman Rickover's nuclear navy program, including both nuclear marine propulsion and the development of a solid-fuel submarine rocket. During the 1950s and early 1960s, Britain's nuclear deterrent was based around the Air Force's V-bombers. But in the early 1960s developments in radar and surface-to-air missiles made it clear that bombers were becoming vulnerable, and would be unlikely to penetrate Soviet airspace. Free-fall nuclear weapons would no longer be a credible deterrent.

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