Britain’s fleet of nuclear-powered hunter-killer submarines could be doubled in a landmark deal with the US and Australia.

Rishi Sunak after a meeting with the US president, confirmed a multibillion-dollar deal with two allies to help design and build ships Joe Biden and Prime Minister of Australia Anthony Albanese at the naval base in California.

The initiative represents some of the first concrete steps taken by the three countries to strengthen the Aukus strategic partnership they announced 18 months ago.

Britain and the US will supply Australia with nuclear submarines for the first time, boosting its ability to counter the threat posed by China’s growing military ambitions.

As part of the deal, British military chiefs are pushing to increase the size of Britain’s fleet of hunter-killer submarines from seven to 20.

Britain’s fleet of nuclear-powered hunter-killer submarines could be doubled in landmark deal with US and Australia

Rishi Sunak and Colonel Jamie Norman, Prime Minister’s Military Attaché (left), First Sea Lord Admiral Sir Ben Key KCB CBE (second right) and Royal Navy Captain Gus Carney (right)

The move comes as Mr Sunak warned that the UK faces a “difficult and dangerous decade” as authoritarian powers such as Russia, China and Iran play their muscles.

A government source admitted the assessment of foreign and security policy in the new integrated review was “dismal” but said it was right to “level with people” the fact that the world had become a more dangerous place.

The Aukus deal is a major coup for British engineering and is expected to create thousands of jobs in the coming years in Barrow, Cumbria, where UK submarines are built, and Derby, where Rolls-Royce designs and manufactures nuclear submarine reactors.

Speaking last night at the Point Loma Naval Base in San Diego, the prime minister said the deal made a reality of John F. Kennedy’s dream of a West united by the “supreme purpose of maintaining freedom, peace and … security.”

The initiative represents some of the first concrete steps taken by the three countries to strengthen the Aukus strategic partnership they announced 18 months ago

Defense Secretary Ben Wallace said: “This is a significant step forward for our three countries as we work together to contribute to security in the Indo-Pacific region and around the world.”

President Biden said Britain, the United States and Australia “have stood together to defend freedom and democracy for more than a century.”

He said the three allies “who have shed blood together in defense of our shared values” had come together again to agree on “the most significant multilateral defense partnership in generations”. He added: “The Aukus partnership and the submarines we are building in British shipyards are a tangible demonstration of our commitment to global security.”

The Aukus Pact was created in 2021 to strengthen defense ties and strengthen the West’s presence in the Indo-Pacific region, where China poses an increasing threat.

In the short term, the Australian Navy is expected to buy five Virginia-class submarines from the United States. But from the early 2030s, Britain and Australia will be building an upgraded version of Britain’s Astute-class submarine.

Defense Secretary Ben Wallace said: “This is a significant step forward for our three countries as we work together to contribute to security in the Indo-Pacific region and around the world.” President Biden said that Britain, the United States and Australia “have stood together for more than a century to defend freedom and democracy.”