THE HAGUE, Netherlands — Britain said it would buy 12 F-35A stealth fighter-bombers, enabling the country’s military to once again have the capacity to deliver nuclear weapons from the air, in an announcement timed to this week’s NATO summit in The Hague.

The new planes, once delivered, can carry both conventional and nuclear bombs. For now, Britain has only one leg of the triad of nuclear weapons delivery systems: Trident submarines that can fire ballistic missiles. Adding air capability, as the French also have, will make it easier for Britain to act in the case of a crisis. Neither country has any land-based nuclear weapons.

Britain also said Tuesday that it would join NATO’s airborne nuclear mission, with allied aircraft being equipped with American B61 bombs stockpiled in Europe. The new planes reintroduce “a nuclear role” for Britain’s air force “for the first time since the U.K. retired its sovereign air-launched nuclear weapons following the end of the Cold War,” the government said.

No. 10 Downing St. called it “the biggest strengthening of the U.K.’s nuclear posture in a generation.” It also strengthens the European pillar of NATO at a time of persistent doubts over the U.S. commitment to use nuclear weapons to defend Europe in the case of a Russian attack.

Seven NATO members, including Germany and Italy, have dual-capable aircraft stored on European soil that can carry American B61 nuclear warheads.

Britain already operates F-35B jets that can operate from aircraft carriers, but they are not equipped to drop nuclear warheads.

Justin Bronk, a senior research fellow at the Royal United Services Institute, which specializes in security issues, said the F-35A was cheaper, had greater range and could carry a broader array of weapons. “These include weapons designed to destroy Russian air defense systems,” he said, “which cannot fit into the smaller weapon bays of the F-35B.”

The announcement follows a stark warning from a government-commissioned security review, issued Tuesday, that the country needs to prepare for the possibility of armed conflict on British soil.

“For the first time in many years, we have to actively prepare for the possibility of the U.K. homeland coming under direct threat, potentially in a wartime scenario,” the document said.

It added that the international order was being “reshaped by an intensification of great power competition, authoritarian aggression and extremist ideologies” and said that Britain’s armed forces would invest in “greater lethality, warfighting readiness, deeper stockpiles of munitions” and new technology.

The decision to add an airborne nuclear capability to Britain’s permanent at-sea deterrent was foreshadowed in a strategic defense review, published this month, that was led by George Robertson, a former NATO secretary-general. That report identified Russia as posing an acute threat and called for Britain to build up to a dozen new attack submarines and invest billions of pounds in weapons.

The F35-A aircraft will be deployed as part of NATO’s nuclear mission, the government said, using weapons over which the United States retains ultimate control.

That prompted questions in the British Parliament where Mike Martin, a lawmaker for the Liberal Democrats and an army veteran, said: “In an age of uncertainty over the reliability of our U.S. allies, it does seem an odd choice to be leaning into them.”

Martin asked whether the decision on the F-35A jets was a “steppingstone to a fully sovereign U.K. capability.” Maria Eagle, a defense minister, said it wasn’t, adding that she hoped that the new aircraft would be delivered by the end of the decade.

David Blagden, of the strategy and security institute at the University of Exeter, said the main rationale for F-35A jets would be to deter Russia by having the option of limited nuclear strikes if the United States was unwilling or unable to protect Britain. But he noted: “Buying another U.S.-made aircraft, with U.S.-controlled source code, to carry U.S.-owned nuclear weapons actually deepens U.K. dependence on U.S. goodwill.”

After decades of relative peace in Europe, the size of the British army is currently lower than at any time since the Napoleonic era. The government is investing in a recruitment and retention drive and earlier this year said it would divert resources from its international development aid budget to military spending.

On Monday, Prime Minister Keir Starmer signed up to a new NATO target of devoting 5% of the country’s economic output to security by 2035. That would be made up of 3.5% on military spending with the remaining 1.5% coming from other security and infrastructure-related spending.

“We can no longer take peace for granted, which is why my government is investing in our national security, ensuring our Armed Forces have the equipment they need,” Starmer said in a statement.

With the government under acute financial pressure domestically and the British public facing continued cost-of-living pressures, some critics have questioned how the additional military spending commitments will be paid for and whether they will come at the expense of other priorities.

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This article originally appeared in The New York Times.

By Steven Erlanger and Stephen Castle
c. 2025 The New York Times Company