Dreadnought-class submarine

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.
Provisionally named "Successor" (being the successor to the Vanguard class SSBNs), it was officially announced in 2016 that the first of class would be named Dreadnought, and that the class would be the Dreadnought class. The next three boats will be called Valiant, Warspite and King George VI.