HMS Vengeance (S31): The Youngest of the Nuclear Four

The Last of the Class, Constructed at Barrow

HMS Vengeance was built by Vickers Shipbuilding and Engineering Limited at Barrow-in-Furness, laid down in February 1993 as the fourth and final Vanguard class boat, following HMS Vanguard, HMS Victorious and HMS Vigilant into service.

That she exists at all was an open question for a while. The order for the fourth boat was placed in July 1992, at about the least promising moment imaginable for a ballistic missile submarine. The Berlin Wall had come down, the Soviet Union had formally dissolved the previous December, and a serious argument was running in Parliament and the press about whether Britain needed four of these things or could get by with three. The order went through, and Vengeance was laid down at Barrow on 1 February 1993, thirteen months after the state she had been designed to deter had stopped existing.

The case for building her was arithmetic rather than politics, and it is the same arithmetic the fleet still runs on. Continuous At Sea Deterrence means one boat on patrol at every moment without exception. Sustaining that needs a second working up or handing over, a third in maintenance, and a fourth in the long refit and refuelling each boat requires once in her life. Three can manage it for a time. Four can manage it indefinitely. The argument was won and she was built, which is why the whole thing did not simply stop when the fleet later ran short. HMS Vanguard carries what that has cost in practice.

She was launched in September 1998 and commissioned in November 1999, entering service with the 1st Submarine Squadron at HM Naval Base Clyde, Faslane, where she remains based today, carrying Trident II D5 ballistic missiles as part of the Royal Navy's Continuous At Sea Deterrent, the standing commitment, unbroken since 1969, to keep at least one of these boats on patrol at all times.

The name has been used sparingly and its last holder had one of the longest careers of any ship Britain ever built. HMS Vengeance (R71) was a Colossus class light fleet carrier completed in January 1945, too late to do much in the Pacific, and she then wore more flags than most ships see commanding officers. She was lent to the Royal Australian Navy from 1952 to 1955 as a stopgap while HMAS Melbourne was being finished, came home, was sold to Brazil in December 1956, was rebuilt at Rotterdam and recommissioned in 1960 as Minas Gerais. She was still operating aircraft in 2001, fifty-six years after she was completed.

She was not the only one of that class to go south and stay there. HMS Venerable was sold to the Netherlands and then to Argentina, became the Veinticinco de Mayo, and spent the Falklands War being hunted by British submarines. Cheap wartime carriers built to be used up in a hurry, and two of them still at sea under other flags forty years later. There is a pleasing contrast in the name passing from a ship like that to a submarine whose entire purpose is that she is never used at all.

Understandably, the Royal Navy's own account of her service is deliberately thin on operational detail, submarine deployments being, by their very nature, a secretive business. The gaps in the public record are better left as gaps than filled with guesswork.

A Refit That Was Not the One You May Have Heard About

It is worth a word of clarification here, since the Vanguard class's refit history has attracted a good deal of press attention in recent years, almost all of it about a different boat. HMS Vanguard's own second refit famously overran spectacularly, stretching to more than seven years against an original four year estimate.

Vengeance's equivalent refit and refuelling, carried out at Devonport, was a considerably more orderly affair by comparison, she entered dry dock in March 2012 under a £350 million contract originally planned to take around three and a half years, involving a new reactor core intended to see out the rest of her service life without needing refuelling again, alongside renewal of her machinery, electronics and weapons systems.

The work was completed in December 2015, broadly in line with her sister boats Victorious and Vigilant, whose first refits averaged around forty two months, a remarkably unremarkable outcome next to Vanguard's well publicised troubles.

Getting to Devonport in the first place required Vengeance to transit up the River Tamar, large enough a spectacle that the Torpoint and Cremyll ferries had to be suspended for safety while she passed.

A Missile Test That Made the Papers

In June 2016, as part of her post-refit demonstration and shakedown operation off the coast of Florida, Vengeance fired an unarmed Trident II D5 missile that suffered a malfunction during its test flight and never reached its intended target area off West Africa.

The Ministry of Defence did not make this public at the time, and it only became widely known some seven months later, after the vote in Parliament to renew the Trident programme, when it was reported by the press, prompting accusations of a cover up.

The government maintained that Vengeance and her crew had been successfully tested and certified regardless, while critics, including a former First Sea Lord, called the silence surrounding the incident bizarre. It remains a disputed episode in the detail, and a good deal of what was written at the time went well past anything that was ever confirmed.

Where the reporting and the official position part company is on what the missile actually did. The Sunday Times account, which is where the story came from, had it veering towards the American coast. Other accounts have it simply running the wrong way and then destroying itself automatically, which is what a Trident is built to do when its guidance concludes it is not where it should be. The Ministry of Defence has confirmed neither version. The direction the missile took remains the one part of the episode with no public answer, and the confident versions in circulation are confident about something nobody outside the programme knows.

What has changed since is that it happened again. On 30 January 2024, HMS Vanguard fired an unarmed Trident II off Florida with the Defence Secretary and the First Sea Lord watching, and the missile's first stage failed to light. It dropped back into the sea near the submarine. That makes two consecutive British test firings that did not work, in 2016 and 2024, from a programme that fires one only every few years: each shot costs millions and consumes a missile from the common pool Britain shares with the United States Navy at King's Bay.

The Ministry of Defence said much the same thing on both occasions, and the point is fair as far as it goes. A Demonstration and Shakedown Operation exists to test the boat and her crew rather than the missile: whether the submarine can get to the right place unnoticed, hold it, and go through the sequence correctly. On that measure both boats passed and both were certified. The submarine did what she was built to do. It is the thing she fires that has now failed twice in front of witnesses, and a deterrent works on the assumption that it would not.

One of the Longest Patrols on Record

In March 2024, Vengeance returned to Faslane after a patrol lasting some two hundred and one days, six and a half months submerged, reported at the time as among the longest deterrent patrols in Royal Navy history.

The ranking can now be set out, with one caveat that matters. The Royal Navy does not confirm which boat is on any given deterrent patrol, so the lengths are published but the names attached to them come from reporting rather than from the Navy. On that basis the sequence runs: a hundred and ninety-five days in September 2023, usually credited to Vigilant; Vengeance's two hundred and one in March 2024; two hundred and four in 2025 and two hundred and five in the spring of 2026, both generally put down to Vanguard. Four records in under three years, which says a great deal more about the state of the rota than about any one crew.

The unusually long patrols in this period were widely attributed to reduced fleet availability while Vanguard remained in her prolonged refit and Victorious underwent deep maintenance of her own, leaving as few as two boats to cover a rota built for four.

Visible wear on Vengeance's hull on her return, rust staining and missing anechoic tiles among them, was noted at the time as a quiet testament to the strain of extended service.

Still on Patrol, Still Waiting for Her Replacement

Vengeance remains in active service today, the youngest of the four Vanguard class boats yet already well past the twenty five year service life originally envisaged for the class when she was designed.

She and her three sisters must continue to carry the deterrent until they are replaced, one by one, by the incoming Dreadnought class submarines, whose lead boat is not expected to enter service until the early 2030s.

No confirmed retirement date exists for Vengeance specifically, only the broader expectation that she will serve on for some years yet, a particularly remarkable span of service for a submarine already older than most of the crew who sail in her.

It makes a strange shape for a career. She was ordered by a government arguing about whether she was needed, laid down after the enemy she was designed for had ceased to exist, and has spent twenty-six years doing a job that is only ever visible when something goes wrong with it. She is the youngest of four boats now all being asked for more than they were built to give, on a rota that has produced four record-length patrols since 2023. The unbroken run she is part of was begun by HMS Resolution and the Polaris boats, and holding it together has come down to a handful of crews doing six and a half months at a time in the dark.

This is a live article which will be updated when more information is available.