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British Prime Minister Keir Starmer, left, followed by Chancellor of the Exchequer Rachel Reeves and Defence Secretary Dan Jarvis arrive for the announcement of a defense plan, in Berkshire, England on Tuesday.Stefan Rousseau/The Associated Press

Self-flying fighter jets, uncrewed submarines and drones will be at the centre of Britain’s future military under a defence plan announced Tuesday that includes a £15-billion (US$20-billion) spending boost.

Like other NATO countries, the U.K. is under pressure to increase defence spending to counter a more aggressive Russia and less reliable United States. But its Defence Investment Plan has been repeatedly delayed as military leaders and Treasury officials wrangled over the cost.

Prime Minister Keir Starmer said the plan reflects a world of conflicts transformed by technology and will keep Britain safe in “a more dangerous and volatile world.”

“When the world is arming and aggression is rising, the best way to avoid war is to prepare for it,” he said.

But the blueprint does not commit to spending three per cent of U.K. GDP on defence by 2030, one of the factors that spurred John Healey to resign as U.K. defence secretary on June 11. Healey accused the government of underspending on the military at a time of “rising threats,” citing a British intelligence assessment that Russia could attack a NATO member country by 2030.

U.K. defence minister resigns over military spending dispute, in blow to embattled Starmer

In the House of Commons on Tuesday, Healey said that “with European security at stake,” Britain needs “to develop a clear, credible funding plan that will hit three per cent and that will meet our NATO commitment of 3.5 per cent by 2035.”

Starmer said Healey’s successor, Defence Secretary Dan Jarvis, had worked to “sharpen and strengthen” the plan. Its £15-billion in new spending is more than the £13.5-billion (US$18-billion) Healey was offered by the Treasury, but far less than the £28 billion (US$37-billion) that defence officials had called for.

U.K. faces pressure to hit NATO target

Under the plan, defence spending will hit 2.7 per cent of GDP by 2029. Starmer said the three per cent target will be reached “in the next Parliament,” a period that could extend to 2034. The U.K. remains committed to hitting NATO’s 3.5 per cent target by 2035, though it’s unclear how it will get there.

The government said the new funding will boost spending on defence to almost 300 billion pounds ($400 billion) over the next four years. Big-ticket items include five billion pounds (US$6.6-billion) for drone technology, eight billion pounds (US$10.6-billion) to build new stealth fighter jets alongside Japan and Italy, and £11-billion (US$14.5-billion) to increase weapons stockpiles. The U.K. will also spend £64-billion (US$85-billion) modernizing its nuclear weapons.

Starmer said some road and energy projects would be scrapped to help pay for the military.

The U.K. military is seeking to reverse years of decline in the face of an increasingly assertive Russia, which invaded its neighbour Ukraine in 2022 and increasingly tests the defences of European nations with overt and covert activity.

The U.K. has watched how drones have transformed war in Ukraine, which uses 200,000 of them a month to defend against Russian forces. Britain plans to invest billions in drone systems across all branches of the military. Instead of a planned fleet of new destroyers, the Royal Navy will get hybrid vessels that will act as command hubs for drones.

“The very nature of conflict is changing before our eyes,” Starmer said during a speech at a drone manufacturer near London. He said that, armed with cutting-edge technology, Ukrainian forces have destroyed Russia’s Black Sea fleet, “struck deep into Russian territory and stopped the advance of one of the biggest armies in the world.”

British PM Keir Starmer says he will resign by September

Critics say more money is needed

Britain and other NATO member nations have faced pressure from U.S. President Donald Trump to increase military spending. Trump has long questioned the value of the military alliance and complained that the United States provides security to European countries that don’t pull their weight.

The resignations of Healey and junior Defence Minister Al Carns were among a series of blows that prompted Starmer to announce last week that he will resign. A NATO summit in Turkey on July 7 and eight may be his final overseas trip as prime minister.

His replacement, likely the former Greater Manchester Mayor Andy Burnham, will be under pressure to stick to the commitments in the defence plan.

“It is a platform on which I know my successor will build,” Starmer said.

Opposition Conservative Party defence spokesperson James Cartlidge said the plan was “too little, too late.”

And retired Gen. Richard Barrons, who helped lead a defence review in preparation for the investment plan, said “we have to find more money for defence sooner.”

“We’re not keeping up with our allies, we’re certainly not keeping up with our enemies, and we know that the U.S. is no longer going to come and save European security in the face of a Russian threat,” he told the BBC.

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