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

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

Sir Keir Starmer will say up to 12 conventionally-armed nuclear-powered submarines will replace the UK’s current fleet from the late 2030s onwards.

The prime minister is also expected to confirm the UK will spend £15bn on its nuclear warhead programme.

Sir Keir will say that, alongside the UK’s nuclear-armed submarines, the new vessels would keep “Britain and Nato safe for decades”.

The Strategic Defence Review, commissioned by Labour, will shape the UK’s armed forces for years to come.

Led by ex-Labour defence secretary Lord Robertson it will make 62 recommendations, which the government is expected to accept in full.

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”.

Building the new submarines will support 30,000 jobs into the 2030s as well as 30,000 apprenticeships and 14,000 graduate roles across the next 10 years, the Ministry of Defence said.

Healey said: “Our outstanding submariners patrol 24/7 to keep us and our allies safe, but we know that threats are increasing and we must act decisively to face down Russian aggression.”

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.

In the Astute series, HMS Agamemnon, was launched last October and another is under construction which will take the number of submarines in this class to seven.

The next generation of attack submarines that will replace them, SSN-AUKUS, have been developed with the Australian Navy under a deal agreed in 2023 by the Conservative government.

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.