Prime Minister Rishi Sunak is flying to the United States on Sunday for defence talks with President Joe Biden and Australian Prime Minister Anthony Albanese.
One of the items on the agenda will be the next phase of the AUKUS nuclear submarine programme.
AUKUS, announced in September 2021, is a pact under which the UK and US are assisting Australia in acquiring nuclear-powered submarines.
It has been reported in The Telegraph that Britain will design Australia’s first generation of such vessels.
Downing Street said the AUKUS programme “exemplifies the UK’s approach”, adding: “We will build rock-solid global alliances and ensure the UK is at the cutting edge of defence capability, technology and economic resilience.”
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Mr Sunak said AUKUS is “binding ties to our closest allies and delivering security, new technology and economic advantage at home”.
He added: “In turbulent times, the UK’s global alliances are our greatest source of strength and security.”
The trip takes place as the government prepares to publish an update to the 2021 Integrated Review, which Downing Street said would “set out how the UK will respond to growing global volatility which threatens British prosperity and security”.
It added: “The Integrated Review refresh will address the grave risks from Putin’s Russia, the increasingly concerning behaviour of the Chinese Communist Party, and hybrid threats to our economy and energy security.”
The PM said: “As we launch the 2023 Integrated Review refresh tomorrow, this is the future we want to deliver – a UK that is secure, prosperous and standing shoulder-to-shoulder with our partners.”
It is a second overseas trip for Mr Sunak in just three days following his visit to Paris on Friday, when he announced a new agreement with France on migration.
Britain will pay out £480m over the next three years in a deal struck between the PM and Emmanuel Macron to tackle small boat Channel crossings, with measures including funding for a new detention centre in France.