Key facts
- HMS Vengeance's 140-strong crew spent 217 days submerged, the longest deployment at sea for a British vessel, per the Ministry of Defence account.
- Defence Secretary Wes Streeting said it "doesn't sit lightly" with him that crews serve longer than intended.
- First Sea Lord Gen Sir Gwyn Jenkins said the UK must do better at maintaining the fleet.
- HMS Victorious is in dry dock for a £560m deep maintenance that began in 2023, leaving three Vanguard-class boats operational.
- The Vanguard-class boats were built for a 25-year service life and are now expected to serve up to 40 years.
HMS Vengeance, a Royal Navy submarine carrying Trident nuclear missiles, returned to HM Naval Base Clyde at Faslane, near Helensburgh, Argyll and Bute, on November 15, 2026, after 217 days submerged on patrol. The 140-strong crew set out on April 12 and spent the tour in near-total isolation beneath the surface.
Defence Secretary Wes Streeting was at the base to welcome the crew home after what the BBC reported as the longest deployment at sea for a British vessel. Streeting said it "doesn't sit lightly" with him that crews were being asked to serve longer than intended, and said the country could be "extraordinarily proud" of its submariners and its nuclear deterrent.
The typical patrol length for the UK's Vanguard-class ballistic missile submarines has more than doubled in recent years, with six-month tours now routine because of a shortage of seaworthy vessels. HMS Vengeance had been expected back at Faslane the weekend before November 15, but the return was reported to have been delayed when the submarine replacing it on patrol had to go back to base to fix a technical fault.
First Sea Lord Gen Sir Gwyn Jenkins praised submariners for keeping NATO safe at a conference in Oslo the week before November 15, but said the UK must do better at maintaining the fleet. Streeting said the Dreadnought-class program to replace the Vanguard boats was "on track" and that it was important to get those vessels out "as soon as possible".
The previous record for a Royal Navy continuous undersea patrol is reported to have been set by HMS Vanguard, which returned to Faslane in April after 205 days away. A major overhaul of HMS Vanguard at Devonport Dockyard in Plymouth ran for seven years before it returned to service in 2022. HMS Victorious is in dry dock for a £560 million deep maintenance that began in 2023, leaving Vengeance, Vigilant and Vanguard operational.