One of Britain’s Trident nuclear submarines has returned to the Faslane naval base in Scotland after an unprecedented seven-month patrol, where its crew is expected to be welcomed by senior government figures.
HMS Vengeance set sail on 12 April and remained submerged for 217 days before surfacing on Sunday. It departed while Keir Starmer occupied Downing Street and Manchester United sat third in the Premier League.
The mission eclipses the previous 205-day record held by the boat’s last crew, sharpening concerns over the demands placed on submariners and the dependability of ageing vessels pushed onto ever-longer patrols.
“Patrols are getting longer and longer,” said David Cullen, a nuclear analyst at the Basic thinktank. “The fleet was designed around three-month tours, and even that was regarded as a long time to be sealed underwater in a metal box with no contact with the outside world.”
The lengthening of time at sea stems largely from sluggish submarine maintenance, a situation Labour attributes to budget cuts made under the Conservatives, although naval leadership maintains that a recovery plan is under way.
HMS Vengeance is one of four submarines that carry Britain’s Trident nuclear deterrent. At least one boat is always at sea, ensuring the UK could retaliate even after a nuclear strike had already devastated the country.
When the Vanguard-class submarines entered service in the 1990s, they were built to store three to four months of provisions for a crew of roughly 140, and patrols exceeding 100 days were treated as highly unusual. Today, missions begin with tinned food packed into corridors and any spare space available.
Because each submarine must conceal its position to avoid being targeted, it cannot be resupplied while submerged. The boats observe strict radio silence, so crew members cannot send messages home during lengthy deployments, though they can still receive news and other information.
The patrols run so long that a returning Trident submarine, referred to as a “day zero,” has become a political occasion in its own right. Starmer paid an unannounced visit when the previous patrol ended in April, offering his thanks to the returning crew.
These gestures also reflect mounting unease about the psychological toll of such missions on submariners, who spend seven months confined aboard a vessel some 150 metres long, at a moment when the Royal Navy is finding it difficult to attract new recruits.
Last week, Gen Sir Gwyn Jenkins, the head of the Royal Navy, said he held “nothing but tremendous respect” for the Trident crews, but stressed that Britain must “improve our submarine maintenance” to enable quicker turnaround times.
Like the wider navy, the submarine service enforces a “no touching rule” that bars physical intimacy on board, though the branch has faced allegations of sexual abuse and harassment during deployments.
In October 2024, the then first sea lord was compelled to apologise to women, who account for about 10% of the navy, after reports of “misogyny, bullying and other unacceptable behaviours” within the submarine service.
A naval inquiry followed complaints from a whistleblower, Sophie Brook, who described enduring a “constant campaign of sexual bullying” at the hands of male sailors. The heavily redacted report examined accounts of rape as well as physical and verbal abuse.
Each Trident submarine can hold up to 40 nuclear warheads, packing sufficient destructive force to level Moscow and several other major Russian cities, alongside a letter from the prime minister instructing the captain on how to act if Britain is judged to have ceased to exist following an all-out nuclear attack.
So protracted is the patrol that HMS Vengeance will still be carrying Starmer’s letter, while the replacement boat now rotating onto station holds Andy Burnham’s instructions, penned in longhand in the days after he entered Downing Street.
In July, Labour set out a £26bn, 10-year programme to upgrade Britain’s three principal naval bases at Faslane, the operational home of the Trident fleet, along with Devonport and Portsmouth, as part of a broader rise in defence expenditure.
Yet the first of the successors to the four Vanguard-class submarines, HMS Dreadnought, is not expected to enter service until around 2032, leaving the existing boats at least another five years of active duty.
“The inherent dangers of operating submarines are being amplified by the way they are being run. In the final years of a submarine’s design life, it should be handled gently rather than worked as hard as it is,” Cullen said.