Britain to build up to 12 attack submarines as it moves to war-ready footing

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Britain will build roughly a dozen new attack submarines as it moves to a state of “warfighting readiness”, Sir Keir Starmer will say on Monday, as he begins what he claims will be a major rearmament programme.

The UK prime minister, speaking at the launch of a long-awaited strategic defence review, will promise major investment in submarines, long-range missiles, cyber defence and £1.5bn on at least six new munitions factories.

But defence secretary John Healey on Sunday refused to say whether chancellor Rachel Reeves had guaranteed the money to meet his “ambition” to spend 3 per cent of Britain’s GDP on defence in the next parliament.

He also admitted he was still trying to stop a net fall in the size of Britain’s army, in spite of the threat posed by Russia, after what he described as “a 15-year recruitment and retention crisis in our forces”.

The expansion of Britain’s conventionally armed, nuclear-powered submarine fleet by “up to” 12 boats by the end of the 2030s comes as part of the UK’s Aukus partnership with Australia and the US and will be at the heart of the country’s effort to remilitarise for a new era of threats.

The new attack submarines are expected to replace seven Astute class submarines by the late 2030s and come alongside £15bn of investment in the UK’s sovereign nuclear warhead programme. Starmer will argue that the defence spending will spread jobs and prosperity around the country.

The 10-year defence review, led by former Nato secretary-general Lord George Robertson, is expected to call for the UK to “move to warfighting readiness” and stick to a pledge to increase the military budget to 2.5 per cent of GDP by 2027.

Starmer’s aim is to hit 3 per cent in the next parliament, after US President Donald Trump urged European countries to boost military spending, although Reeves’ priority at the moment is trying to control state expenditure.

Shadow defence secretary James Cartlidge said the government’s promises should be taken “with a pinch of salt unless they can show there will actually be enough money to pay for them”.

While Britain’s military has largely been an expeditionary force fighting low-tech adversaries overseas since the end of the cold war, it must shift focus to home defence, cyber warfare and peer competitors such as Russia and China, the review is expected to say.

Ministers have vowed to procure up to 7,000 UK-built long-range weapons and spending £1.5bn on building at least six new munitions factories.

They have also set out plans to unify cyber and electronic operations under a single command, and develop the role of artificial intelligence, as part of a sweeping reorganisation of high-tech warfare.

Healey said the moves pointed to how Britain needed to “prepare for war” and “respond to a world of growing threats”. But he conceded that he was struggling to hit the target of a 73,000-strong army, with current numbers short by about 2,000.

Healey did not deny a report in the Sunday Times newspaper that Britain wanted to purchase US-made fighter jets capable of firing tactical nuclear weapons, to counter the growing threat posed by Russia.

Asked by the BBC whether Britain was looking at different ways to launch nuclear weapons — aside from its Trident nuclear submarine deterrent — Healey said: “I won’t get into discussions that need to remain private”.

The SDR, which Starmer launched last year, was led by Robertson with support from ex-White House Russia adviser Fiona Hill and ex-deputy chief of the defence staff General Sir Richard Barrons. They handed in the final iteration of their review in early March.