UK to build up to 12 new attack submarines

Paul Seddon
Political reporter
Jonathan Beale
Defence correspondent@bealejonathan
PA Media Image shows a mocked-up illustration of what an SSN-AUKUS submarine will look likePA Media
An illustration of what an SSN-AUKUS submarine will look like

The UK will build "up to" 12 new attack submarines, the prime minister has announced, as the government unveils its major defence review on Monday.

The new conventionally-armed, nuclear-powered submarines will replace the seven-strong Astute class from the late 2030s onwards.

The review is expected to recommend the armed forces move to "warfighting readiness" to deter growing threats faced by the UK.

Sir Keir Starmer said the government will adopt a "Nato-first" stance towards defence, so that everything it does adds to the strength of the alliance.

The threat posed by Moscow has been a key part of the government's pitch ahead of Monday's review, led by ex-Labour defence secretary Lord Robertson, which was commissioned by Labour shortly after it took office last July.

The report will make 62 recommendations, which the government is expected to accept in full.

Speaking to BBC Radio 4's Today programme ahead of its publication, Sir Keir said the danger posed by Russia "cannot be ignored" and the "best way" to deter conflict was to prepare for it.

The government has committed to increasing UK defence spending from 2.3% to 2.5% of national income by 2027, a move welcomed by opposition parties amid a growing consensus on boosting military expenditure.

The PM told an audience at the BAE Systems' shipyard in Govan, Glasgow that he was "100% confident" the plans - including £15bn on nuclear warheads and thousands of new long-range weapons - could be delivered on current funding plans.

But the run-up to the review's release has been dominated by a political row over when UK spending should hit the next milestone of 3%.

The government says it has an "ambition" to hit the target by 2034 at the latest, after the next general election, but the Conservatives say the move - which would hike spending by around £20bn a year - should be met by the end of the decade.

Sir Keir said he would only commit the government to a timescale when he knew how it could be paid for, adding a date would otherwise be "performative".

Shadow defence secretary James Cartlidge said Labour's review should be "taken with a pinch of salt" unless the government showed there would be enough money to pay for it.

The Liberal Democrats have said Labour's 2034 timeline is "far too late" and have suggested an earlier date should be found in cross-party talks.

The party's defence spokesperson Helen Maguire called for a "concrete commitment" on funding to back up the submarines announcement, adding that Labour had left "serious questions" over how the project would be financed.

PA Media Image shows Prime Minister Sir Keir Starmer in a white shirt and glasses, speaking to workers during a visit to Glass Futures in St Helens, Merseyside, on 29 May, 2025PA Media

Other announcements in the review will include:

  • Commitment to £1.5bn to build six new factories to enable an "always on" munitions production capacity
  • Building up to 7,000 long-range weapons including missiles or drones in the UK, to be used by British forces
  • Pledge to set up a "cyber and electromagnetic command" to boost the military's defensive and offensive capabilities in cyberspace
  • Extra £1.5bn to 2029 to fund repairs to military housing
  • £1bn on technology to speed up delivery of targeting information to soldiers

Defence Secretary John Healey has signalled he is not aiming to increase the overall size of the Army before the next general election.

On Sunday, he said his "first job" was to reverse a decline in numbers with a target to return to a strength of 73,000 full-time soldiers "in the next Parliament".

Submarine plans

The Astute class is the Royal Navy's current fleet of attack submarines, which have nuclear-powered engines and are armed with conventional torpedoes and missiles.

As well as protecting maritime task groups and gathering intelligence, they protect the Vanguard class of submarines that carry the UK's Trident nuclear missiles.

The sixth submarine in the current Astute series was launched last October, with the seventh, the final one in the series, currently under construction.

The next generation of attack submarines that will replace them, SSN-AUKUS, have been developed with the Australian Navy under a deal announced in 2021 under the previous Conservative government.

The Ministry of Defence (MoD) said it expected the rollout of the new generation would see a submarine built every 18 months.

It added the construction programme would see a "major expansion of industrial capability" at BAE Systems' shipbuilding site in Barrow-in-Furness, Cumbria, as well as the Derby site of Rolls-Royce, which makes nuclear reactors.

Meanwhile work on modernising the warheads carried by Trident missiles is already under way.

The £15bn investment into the warhead programme will back the government's commitments to maintain the continuous-at-sea nuclear deterrent.

In his announcement on Monday, Sir Keir is to repeat a Labour manifesto commitment to deliver the Dreadnought class of nuclear-armed submarines, which are due to replace the ageing Vanguard fleet from the early 2030s onwards.

The MoD's Defence Nuclear Enterprise accounts for 20% of its budget and includes the cost of building four Dreadnought class submarines.