Britain and the United States have signed a major technology agreement set to inject billions of pounds into the UK economy, coinciding with President Donald Trump’s second state visit.

Prime Minister Sir Keir Starmer hailed the deal as “a general step change” in UK-US relations, promising “growth, security and opportunity across the country.”

The “tech prosperity deal” will foster collaboration in artificial intelligence, quantum computing, and nuclear power.

The Prime Minister said, “This tech prosperity deal marks a generational step change in our relationship with the US, shaping the futures of millions of people on both sides of the Atlantic, and delivering growth, security and opportunity up and down the country.”

It accompanies £31 billion in US investment from leading tech companies, including $30 billion (£22 billion) from Microsoft, the largest investment the company has ever made in the UK.

Microsoft’s funds will expand Britain’s AI infrastructure and build the country’s largest AI supercomputer.

Microsoft’s vice chairman and president, Brad Smith, said the investment reflects “many conversations” with the UK Government and noted it “would have been inconceivable because of the regulatory climate” in previous years.

“You don’t spend £22 billion unless you have confidence in where the country, the Government and the market are all going,” he said.

“And this reflects that level of confidence.”

Officials said the tech partnership’s investment could accelerate the development of new medicines and foster joint research in fields including space exploration and defence.