The Astute class is the latest class of nuclear-powered fleet submarines (SSNs) in service with the Royal Navy. The boats are being constructed by BAE Systems Submarines at Barrow-in-Furness. Seven boats will be constructed: the first of class, Astute, was launched by Queen Camilla, in 2007, commissioned in 2010, and declared fully operational in May 2014. The Astute class is the replacement for the Trafalgar-class fleet submarines in Royal Navy service.

The Dreadnought class is the future replacement for the Royal Navy's Vanguard class of ballistic missile submarines. Like their predecessors they will carry Trident II D-5 missiles. The Vanguard submarines entered service in the United Kingdom in the 1990s with an intended service life of 25 years. Their replacement is necessary for maintaining a continuous at-sea deterrent (CASD), the principle of operation behind the Trident system.