HMS Vengeance returns after record 217-day submerged patrol

HMS Vengeance has returned to its Scottish base after spending 217 days submerged on patrol, the longest deployment at sea by a British vessel, according to the BBC. The Royal Navy submarine carries Trident nuclear missiles and set out from Faslane on 12 April with a crew of 140.

Defence Secretary Wes Streeting welcomed the crew at HM Naval Base Clyde. He said it “doesn't sit lightly” with him that submariners were being asked to serve longer than intended, and praised their commitment and professionalism.

The record comes amid pressure on the UK’s ageing Vanguard-class fleet. Patrols that once typically lasted three months have stretched to six months or more as boats have been unavailable for refits or repairs. HMS Victorious is undergoing deep maintenance, while a technical fault on the submarine due to replace Vengeance reportedly delayed Vengeance’s expected return last weekend.

The previous Royal Navy record for a continuous undersea patrol was set by HMS Vanguard, which returned in April after 205 days away. The four Vanguard-class submarines entered service in the 1990s and are expected to serve until the first Dreadnought-class boats begin replacing them in the early 2030s. Streeting said the replacement programme was “on track”.

The UK has kept at least one ballistic missile-armed submarine at sea continuously since 1969 as part of its nuclear deterrent. To avoid detection, submarines remain submerged and in radio silence during patrols; crew contact with family is limited, with weekly messages capped at 120 words.