Britain is no longer Europe’s “center of gravity” in the eyes of America - and particularly if Joe Biden is elected president next month — according to former senior diplomat and cross-bench peer Peter Ricketts.

After 40 years defending Britain’s interests in the world, Ricketts offered a sobering interpretation of the impact Brexit is having on the U.K.’s international standing.

“When Biden looks towards Europe, he will see Paris and Berlin more as the center of gravity of what’s really important for America in Europe, both economically and in security terms, and Britain will be seen rather as an outlier, rather outside the mainstream of Europe,” he said.

“There will continue to be an important bilateral relationship on defense and security of course, but in other areas, Britain will not have the same prominence it has been used to having in Washington because, frankly, Britain is less useful to the U.S. administration.”

The U.K.’s former ambassador to Paris and NATO and longtime critic of Boris Johnson now spends his time scrutinizing government policy on security and justice in the House of Lords, researching conflict and security topics as a visiting professor at King’s College London, and advising aerospace company Lockheed Martin U.K.

With the U.S. election just a week away, Ricketts is the latest in a string of former diplomatic heavyweights to offer Downing Street advice about how to navigate a possible change of the guard in the White House.

Ivan Rogers, who was the U.K.’s permanent representative in Brussels from 2013 to 2017, told the Observer Johnson is biding his time to see the result of the U.S. presidential election before deciding whether to opt to leave the European Union without a trade deal. While Downing Street rejected Rogers’ theory, telling POLITICO’s London Playbook it was “demented,” the U.K. government, along with the rest of the world, is certainly watching events across the Atlantic with interest.

Speaking to POLITICO from his home in London, Ricketts said a Biden victory in the U.S. presidential election on November 3 will usher in a “much less confrontational, more courteous and consultative style” towards America’s international partners, Britain included. But, he added, Downing Street should not delude itself thinking this will make its dealings with the U.S. any easier.

'Thin' Brexit deal still likely

Many in Europe will be “encouraged” if Biden wins, Ricketts said, and will be “eager to establish new relations” with the new White House, probably pushing Brexit down Europe’s list of priorities.

The EU and the U.K. are immersed in an intensified period of Brexit negotiations, with EU negotiator Michel Barnier and his team now expected to remain in London until Wednesday with talks continuing in Brussels after that. Both sides hope a trade deal can be struck in the next two to three weeks, which can then be ratified in time for the end of the Brexit transition period on December 31.

The British government would face the challenge of building relations with Biden’s team, who view Brexit as a risk to both Europe and Britain’s stability, Ricketts said. Biden already sent a warning shot last month, when he tweeted that “the Good Friday Agreement that brought peace to Northern Ireland” cannot become “a casualty of Brexit.”

The U.K. must prepare for a Biden administration that keeps a particularly close eye on how Brexit affects Ireland, given the Irish influence in the Democratic party and Biden’s own Irish background. Biden’s administration will prioritize trade with the EU just as the U.K. “has put itself out of an influential position in Europe,” Ricketts said.

“The Biden administration would be very careful, very prudent about how to deal with this Brexit Britain,” he added.

Despite last week’s ping-pong between London and Brussels, which Ricketts rejects as part of Downing Street’s “negotiating theater,” designed to sell any future deal to the hardline Brexiteers of the Conservative party, he is cautiously optimistic about the chances of a EU-U.K. future relationship deal being struck this fall.

The political impasse on issues such as state aid and fisheries may be broken with last-minute phone calls between Johnson and some EU leaders, but Ricketts warned Downing Street against placing its faith in German Chancellor Angela Merkel.

“I’m afraid in London our political leaders have long expected Merkel to solve the problems for us, to pull our chestnuts out of the fire. And usually that has proven wrong, because although she is a very, very serious and thoughtful politician, she can’t do miracles,” he said, adding that he does not believe French President Emmanuel Macron would risk a collapse of the negotiations over fisheries.

“President Macron is playing a card that he knows if he overplays it his fishermen will end up with nothing. So at the end of the day I don’t think fisheries will be the issue in which these negotiations break down.”

A Downing Street spokesperson said Brexit talks had intensified but the U.K. would not accept proposals that "undermine our status as a sovereign, independent country."

“Our trade negotiations with the U.S. are entirely separate from ongoing negotiations with the EU, and they are continuing to progress at pace," the spokesperson said. “We’ll continue to work with whoever the next U.S. president is to ensure a good outcome that benefits both countries.”

Ricketts predicts the U.K. and EU will most likely strike a “thin” deal, leaving out many important aspects for their bilateral cooperation, particularly security and defense - an area of special interest for the chair of the Lords EU security and justice committee, and former national security adviser to former Prime Minister David Cameron.

“You can be sure that any deal that the Johnson government signs will be trumpeted as a great victory and it will be attributed to the tough negotiating tactic that has been followed,” he said. “In practice, I think the EU has been largely setting the agenda through these negotiations, which is partly why Britain has lost reputation as a result.”