Rishi Sunak has hailed the UK’s global alliances as its “greatest source of strength and security” as he prepared to meet US President Joe Biden to flesh out a major defence deal.

The Prime Minister is flying to San Diego on Sunday to discuss the procurement of nuclear-powered submarines under the Aukus pact between the UK, US and Australia.

Australian premier Anthony Albanese will join the pair for the summit, with UK ministers’ hopes high that he will announce the purchase of a British-designed fleet.

While on the US west coast on Monday, Ms Sunak is also set to unveil the new integrated review of defence and foreign policy, which was being updated in the wake of Russia’s invasion of Ukraine.

The refreshed review will set out the UK’s approach to threats from Moscow and an increasingly assertive China.

Ahead of his trip, the Prime Minister said: “In turbulent times, the UK’s global alliances are our greatest source of strength and security.

“I am travelling to the United States today to launch the next stage of the Aukus nuclear submarine programme, a project which is binding ties to our closest allies and delivering security, new technology and economic advantage at home.

“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.”

Mr Sunak last week met with French President Emmanuel Macron, smoothing out relations after they hit a low point with the September 2021 signing of the Aukus deal, which saw Australia ditch France in favour of an agreement with the UK and US.

Negotiations over the last 18 months have presented the Canberra government with a choice between a British or US design.

Reports suggest Australia could opt for a modified version of the British Astute-class submarine, plugging the gap until it enters into service in the 2040s with up to five American Virginia boats.

The UK hopes that Aukus will result in work for British shipyards such as BAE Systems’ facility in Barrow-in-Furness, Cumbria.

Mr Sunak’s first visit to the US as Prime Minister comes in another crucial week for his leadership, with Chancellor Jeremy Hunt setting out the Budget on Wednesday.

Defence minister James Heappey acknowledged there has been “robust” public and private clashes between the Ministry of Defence and Treasury over funding levels.

Defence Secretary Ben Wallace has been arguing for a multibillion-pound hike to his budget.

San Diego, in the state of California, where Mr Sunak used to live, is home to the US Pacific Fleet.