What was the name of the first nuclear-powered submarine built by the United Kingdom?

HMS Dreadnought was the first nuclear-powered submarine built by the United Kingdom.

The Royal Navy commissioned Dreadnought in 1963. The boat used a Rolls-Royce PWR1 nuclear reactor, with the reactor technology developed with substantial American assistance. Its construction marked Britain’s entry into nuclear submarine operations.

Dreadnought was built by Vickers Armstrongs at Barrow-in-Furness. Its design combined a British hull and weapons arrangement with influences from the American Skipjack class, especially the streamlined teardrop-shaped hull intended for high underwater speed.

The name can cause confusion because HMS Dreadnought was also used by a famous battleship launched in 1906. The submarine was a different vessel and belonged to the nuclear-powered era. Britain later built nuclear attack submarines including the Valiant, Swiftsure and Trafalgar classes.