The former director of the US National Economic Council has said it would be “delusional” for the UK to expect a preferential trade deal with the US after Brexit.

Larry Summers, who served under President Barack Obama, said Britain would have “no leverage” in trade talks.

“I’m not sure what Britain wants from the United States that it can plausibly imagine the United States will give,” he told BBC Radio 4′s Today programme on Tuesday morning.

With Boris Johnson having promised to take the UK out of the EU with or without a deal on October 31, Donald Trump has said he wants to agree “a very substantial trade agreement”.

The US president is due to meet the prime minister at the G7 summit in Biarritz, France later this month.

But trade deal would need to be approved by the US Congress. Nancy Pelosi, the Democrat Speaker or the House of Representatives, has warned she will not agree to a deal if Brexit endangered peace in Northern Ireland. 

Senator Chris Murphy, the Democrat from Connecticut who sits on the foreign relations committee, told HuffPost UK last month that Trump would have a “tough time” getting a deal through Congress.

But Republican Senator Tom Cotton told the BBC this morning Britain should be at the “front of the queue” for a trade deal with the US.

“Obviously, it wouldn’t be a matter of days or weeks for such negotiations, it might be months, but I would suspect it would be months, not years,” he said.

Summers, who was also US Treasury Secretary during Bill Clinton’s time in the White House, said: “Look at it from America’s point of view. A: 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.

“Second, 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. The last thing you do is quit a job before you look for your new one.”

He added: “If Britain thinks that the American financial regulators who have great difficulty coming together on anything are going to come together to give greater permissions and less regulation of UK firms, I would call that belief close to delusional.”