The United States is considering ending a nuclear submarine pact with the UK and Australia, in what would be a major blow to a security alliance between the countries.

The Pentagon launched a review of the 2021 Aukus submarine deal to decide if the US should cancel the project, US defence officials said.

The assessment is being led by Elbridge Colby, a defence department official and former Trump campaign aide, who has raised questions about Aukus.

The deal includes a commitment from the US to supply Australia with at least eight nuclear-propelled submarines.

But some inside the Trump administration argue it comes at the expense of America’s own domestic production of submarine defence.

Aukus submarines will feature a Rolls-Royce pressurised water reactor built in the UK, with the UK providing naval training to support the programme.

Aukus also covers AI and missiles

The deal froze France out of a major defence contract with Australia.

On Tuesday, Pete Hegseth, the US defence secretary, insisted the US would supply Australia with a fleet of nuclear-powered submarines, amid growing concern that production is not progressing quickly enough.

Under the Aukus deal, signed to great fanfare in 2021, Washington, London and Canberra are cooperating on the joint development of cyber warfare tools, artificial intelligence and hypersonic missiles.

The agreement commits the United States to building cutting-edge submarines for Australia, an investment with an estimated cost of up to $235 billion over 30 years.

Australia plans to acquire at least three Virginia-class submarines from the United States within the next 15 years, eventually manufacturing its own nuclear-powered subs.

The US Navy has 24 Virginia-class vessels, which can carry cruise missiles, but American shipyards are struggling to meet production targets set at two new boats each year.

Critics have questioned why the United States would sell nuclear-powered submarines to Australia without stocking its own military first.

In a post on X last year, Mr Colby wrote that he was “sceptical” of the agreement.

“In principle [Aukus is] a great idea. But I’ve been very sceptical in practice. I remain sceptical – agnostic as I put it to [The Sydney Morning Herald] – but more inclined based on new information I’ve gleaned,” he wrote. “It would be crazy to have fewer [attack submarines] in the right place and time,” he said.

UK pushing to retain partnership

A British government official told The Telegraph it was aware of the review and was reiterating the importance of the pact to leaders in Washington.

The spokesman said: “Aukus is a landmark security and defence partnership with two of our closest allies.

“It is one of the most strategically important partnerships in decades, supporting peace and security in the Indo-Pacific and Euro-Atlantic, while also delivering jobs and economic growth in communities across all three nations.

China has strongly pushed back against the Aukus deal.

Mao Ning, the spokesman for the Chinese foreign ministry, said in 2023 that Aukus was “about fuelling military confrontation through military collaboration”.

Ms Mao said: “It is apparently driven by Cold War thinking. It creates additional nuclear proliferation risks, exacerbates the arms race in the Asia-Pacific and hurts regional peace and stability.

“China is deeply concerned and firmly opposed to it.”

The biggest threat to China is the pact’s order to supply Australia with at least eight nuclear-propelled submarines, which travel and remain undetected for much longer than the traditional diesel-powered vessels.

The highly advanced nuclear fleet would enable a better understanding of China’s existing sea-based nuclear weapons.

A US defence official said: “The Department is reviewing Aukus as part of ensuring that this initiative of the previous administration is aligned with the President’s America First agenda.

“As Secretary Hegseth has made clear, this means ensuring the highest readiness of our service members, that allies step up fully to do their part for collective defence, and that the defence industrial base is meeting our needs.

“This review will ensure the initiative meets these common sense, America First criteria.”