Donald Trump is “very gung-ho” about a major UK-US trade deal, Boris Johnson said after the two leaders had their first formal meeting.

The Prime Minister was praised by the US President as the “right man for the job” of delivering Brexit and was promised a “very big trade deal” as the pair met in the margins of the G7 summit in Biarritz.

But Mr Johnson played down the prospects of a transatlantic deal being concluded within a year, as he believes Washington wants.

He warned that a deal with the “protectionist” US would not be “plain sailing”.

In a sign of the close relationship between the two leaders, Mr Trump said he had long held his positive views on Mr Johnson’s suitability for being Prime Minister, which “didn’t make your predecessor very happy”.

Both leaders were keen to stress their desire for a trade deal after the UK has left the European Union.

The president said: “We’re going to do a very big trade deal, bigger than we’ve ever had with the UK and now at some point they won’t have the obstacle, they won’t have the anchor around their ankle, because that’s what they have.”

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Prime Minister Boris Johnson meeting US President Donald Trump for bilateral talks during the G7 summit in Biarritz, France (Stefan Rousseau/PA)

But Mr Johnson has raised a series of areas where he wants concessions from Washington.

The president said he wanted a deal done “quickly” because in the past he had been “stymied” under Theresa May.

He added: “This is a different person and this is a person that’s going to be a great Prime Minister, in my opinion.”

But Mr Johnson told the president there would be “tough talks” ahead.

Asked if he had made clear his views on protecting the NHS and animal welfare standards in trade talks with Mr Trump, the Prime Minister told the PA news agency: “There is complete unanimity on that point.”

The Prime Minister also warned Mr Trump against escalating his trade war with China.

“We are in favour of trade peace on the whole,” he said as the two leaders and their teams had a working breakfast at the Hotel du Palais.

In a series of broadcast interviews, Mr Johnson played down the prospect of a rapid deal.

He told ITV: “There’s an opportunity to do a great free trade deal with the United States.

“The president is very gung-ho about that and so am I.”

But he added that “I don’t think people realise quite how protectionist” the US market can be.

“They want to do it within a year, I’d love to do it within a year, but that’s a very fast timetable,” he said.

The two leaders agreed to set up a working group focused on closer economic links.

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Prime Minister Boris Johnson meets European Council President Donald Tusk at the G7 summit (Neil Hall/PA)

US director of the National Economic Council Larry Kudlow and UK Cabinet Secretary Sir Mark Sedwill have been directed to set up the special relationship economic working group (SREWG).

“The SREWG will develop market-oriented principles for economic growth and increase bilateral cooperation on issues related to the modern 21st century economy,” the White House and Number 10 said in a joint statement.

Mr Johnson also had talks on Brexit at the G7 with European Council President Donald Tusk.

A senior UK official said the pair would meet again in September at the United Nations General Assembly.

The official said: “The Prime Minister repeated that the UK will be leaving the EU on October 31, whatever the circumstances. We must respect the referendum result.”

Mr Johnson said the UK would work in an “energetic and determined way to get a better deal and we are very willing to sit down to talk with the EU and member states about what needs to be done to achieve that”.