The UK and the US have tonight announced what their leaders call The Atlantic Declaration, ITV News' Anushka Asthana reports
The Atlantic Declaration could pave the way for British defence companies to access American investment, allow data sharing and recognise professional qualifications in critical industries.
But it falls short of the full free trade deal promised in the Conservative Party's 2019 manifesto, with Mr Sunak admitting that is no longer a priority for him.
He justified the decision to drop the manifesto promise by arguing the world had changed dramatically in the past few years as a result of Covid and the war in Ukraine.
The Atlantic Declaration will also aim to strengthen supply chains to try to prevent a situation in which China and Russia can use economic means to cause disruption.
The plan includes:
Working together to reduce vulnerabilities across critical technology supply chains, including by sharing analysis and consultation during crises.
Supporting the critical clean energy industry to keep Russia out of the global civil nuclear power market.
A commitment in principle to a new UK-US Data Bridge, which would make it easier for businesses to transfer data freely to certified US organisations with less red tape.
Enhancing cooperation between allies to stop adversaries developing and acquiring sensitive technologies.
There will also be more cooperation on artificial intelligence (AI) after Mr Sunak announced plans for a global summit in the UK this autumn.
He wants the UK to become a global leader in regulating AI, but the US already has quite advanced discussions with the EU on a new code of conduct.
The prime minister said: "The UK and US have always pushed the boundaries of what two countries can achieve together.
"Over generations we have fought alongside one another, shared intelligence we don't share with anyone else, and built the strongest investment relationship in world history.
"So it's natural that, when faced with the greatest transformation in our economies since the industrial revolution, we would look to each other to build a stronger economic future together.
"The Atlantic Declaration sets a new standard for economic cooperation, propelling our economies into the future so we can protect our people, create jobs and grow our economies together."
Negotiations will begin on many aspects of the partnership, including on a Critical Minerals Agreement.
The agreements comes after the US took a step in a more protectionist direction, with the Inflation Reduction Act that included massive subsidies for green tech - something British ministers had raised concerns about.
The National Security adviser Jake Sullivan also delivered a speech calling for a new "Washington consensus" that would accept that globalisation has not always worked for US workers and has left the economy vulnerable to shocks from China and Russia.
Speaking on the plane on the way to Washington DC, Mr Sunak insisted that the G7 still believed that protectionism was wrong.
But this agreement does appear to shift towards a more protectionist approach across allies and allows Britain to chip into some of the new barriers that have been put up in the US.
However, it does fall short of that full free trade deal, raising a question of whether it was ever a feasible ambition.
Barack Obama once said that Brexit would put the UK at the back of the queue for a free trade deal with the US - something former chancellor George Osborne suggested had happened last night.
The Partygate: The Inside Story podcast brings you fresh revelations and our whistleblowers in their own words in the definitive behind-closed-doors story of how ITV News uncovered one of the biggest scandals of our era