The United States will dominate the UK in trade talks, according to a former US treasury secretary.

A UK-UK trade deal would hugely favor the US because Brexit has left the UK in a "desperate" position, Larry Summers said on Tuesday.

"Britain has no leverage. Britain is desperate. Britain has nothing else," he told the BBC.

President Donald Trump has promised to negotiate a trade deal that is unprecedented in scope.

Prime Minister Boris Johnson has prioritized a trade agreement with the US once the UK has left the European Union.

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The United Kingdom will struggle to secure a trade agreement with the United States because Brexit will leave it "desperate" and without "leverage," according to Larry Summers, a former US treasury secretary.

UK Foreign Secretary Dominic Raab is set to visit the US this week to help lay the foundations for a wide-ranging trade agreement between the two countries once the UK has left the European Union.

Brexit-backing members of Parliament — including Prime Minister Boris Johnson — argue that a free-trade deal with the US could be one of the biggest benefits of leaving the EU. President Donald Trump has promised a trade deal that is unprecedented in scope.

However, Summers, who had senior positions during the Clinton and Obama administrations, said on Tuesday that the US would agree only to a deal that weighed heavily in its favor.

Read more: Remainer MPs are reportedly plotting to bring down Boris Johnson's government, install a 'unity' prime minister, and delay Brexit

"Britain has no leverage. Britain is desperate. Britain has nothing else. It needs an agreement very soon. When you have a desperate partner, that's when you strike the hardest bargain," he told the BBC Radio 4's "Today" program.

"The last thing you do is quit a job before you look for your new one," he said.

"In the same way, establishing absolutely that as a matter of sacred principle you're leaving Europe has to be the worst way to give you leverage with any new potential partners."

Summers added: "Britain has much less to give than Europe as a whole did, therefore less reason for the United States to make concessions. You make more concessions dealing with a wealthy man than you do dealing with a poor man."

The prospect of a comprehensive trade agreement with the US is strongly opposed by many MPs in Westminster.

There is concern that a trade deal could give US companies high levels of access to British agriculture, flooding the market with cheap goods that would undercut UK businesses and reducing the standards of goods sold in the UK. The Labour Party has claimed that a trade deal with the US would give private American firms access to the National Health Service.

Members of Congress have also said they will not approve any trade agreement that threatens the Good Friday Agreement and the open border between Northern Ireland and the Republic of Ireland.

Naomi Smith, CEO of the pro-EU group Best for Britain, said: "This is the real reason Trump has been talking up a deal. He's no friend of Britain, he just knows Boris Johnson is a pushover and wants to take full advantage.

"Any post-Brexit trade deal with the US will risk our NHS. Trump has already said he wants it on the table, and Johnson doesn't like to make his American master angry.

"Stopping Brexit, and the weak position it has put us in, is the best way to protect our NHS."