Donald Trump has congratulated Boris Johnson on his “great win” in the general election, and said the UK and US would be free to strike a “massive” new trade deal after Brexit.
The American president said the agreement had the potential to be “far bigger and more lucrative” than any deal which could have been made with the European Union.
The Prime Minister’s victory puts Britain firmly on course to leave the EU next month, and he will seek to strike a free trade deal by the end of 2020.
Mr Trump tweeted: “Congratulations to Boris Johnson on his great WIN! Britain and the United States will now be free to strike a massive new Trade Deal after BREXIT.
“This deal has the potential to be far bigger and more lucrative than any deal that could be made with the E.U. Celebrate Boris!”
Trump’s ambassador to the UK, Woody Johnson, predicted that reaching a new agreement would be swift and simple.
Mr Johnson told BBC News: “As far as this president is concerned, [Britain] has never been anything but at the front of the queue [for a trade deal].
“He wants to do a free trade deal that is free, fair and balanced, something both sides have to sign, and he wants to get it done quickly.
“It will be on his desk, and if the president wants to get something done, it does get done.”
Mr Johnson brushed aside any concerns the deal would be “complicated.”
“You can make it complicated or you can make it simple,” he said.
The prospect of a trade deal with the US was a major talking point during the election campaign, with Labour claiming the NHS was at risk of being sold off to US companies in the fallout from Brexit.
Those accusations were denied by both sides, with Mr Trump telling journalists during his recent visit to Britain for the Nato summit that he wants “nothing to do with” the health service.
He added that he had “never even thought about it”, despite stating during a previous visit that “when you’re dealing in trade, everything is on the table”.
The PM and President have a chequered history, with Mr Johnson once joking that he would avoid some parts of New York because of the “real risk” of meeting him.
Last week he was filmed laughing as Canadian PM Justin Trudeau and French President Emmanuel Macron appeared to discuss Mr Trump’s bombastic arrival in the UK.
Nonetheless, Mr Trump has consistently offered his support to Mr Johnson since taking up the Presidency, telling the Sun last year that he would make a “great” Prime Minister, even though Theresa May was still in the role at the time.
The Prime Minister has said he will not extend the transition period once the UK has left the EU beyond the end of 2020.
Therefore he needs to strike a free trade deal with the European Union to avoid the UK leaving on WTO – or no-deal – terms.
However, few trade experts believe this will be possible in that time frame, as they usually take many years.
The Peterson Institute for International Economics think tank said it takes on average one and a half years, for the US to sign a trade deal with a partner and more than three and a half years to get to the implementation stage.