Key point: A sea-based nuclear strike capability is vital for a second strike.
The United Kingdom maintains a fleet of four ballistic missile submarines with the ability to devastate even the largest of countries. This fleet came into being after its ally, the United States, canceled a key weapon system that would have been the cornerstone of London’s nuclear arsenal. Fifty years later, the UK’s missile submarine force is the sole custodian of the country’s nuclear weapons, providing a constant deterrent against nuclear attack.
The United Kingdom’s nuclear force in the early 1960s relied upon the so-called “V-Force” strategic bombers: the Avro Vulcan, Handley Page Victor and Vickers Valiant. The bombers were set to be equipped with the Skybolt air-launched ballistic missile, which could penetrate Soviet defenses at speeds of up to Mach 12.4 (9,500 miles an hour). Unfortunately technical problems plagued Skybolt, and the U.S. government canceled the missile in 1962.
Skybolt’s cancellation threatened to undo the UK’s entire nuclear deterrent, and the two countries raced to come up with a solution. The United States agreed to offer the new Polaris submarine-launched ballistic missile to replace Skybolt. The United Kingdom had no missile submarines to carry Polaris—it would have to build them.
A study by the Ministry of Defense concluded that, like France, the UK would need at least five ballistic missile submarines to maintain a credible deterrent posture. This number would later be reduced to four submarines. Like the French Le Redoutable class, the submarines would bear a strong resemblance to the U.S. Navy’s Lafayette-class ballistic missile submarines, with two rows of eight missiles tubes each behind the sail. Unlike Lafayette and Le Redoutable, the new submarines of the Royal Navy’s Resolution-class would have their hydroplanes on the bow, with the ability to fold up when parked along a pier.