Mr President, I have a Mr Johnson on the line… will you accept the call?

Tommy Vietor, a former Obama press aide, responded to Johnson’s congratulatory tweet last night by calling him a “shapeshifting creep”, adding: “We will never forget your racist comments about Obama and slavish devotion to Trump.”

Tim Shipman, Political Editor 

When Boris Johnson discussed the presidential election with aides on Friday, he was upbeat about developing a special relationship with the winner. “Joe Biden is one of the few world leaders I haven’t insulted,” he joked.

No 10 officials laughed, but this weekend they are engaged in a diplomatic dance following warnings from those close to the president-elect that Johnson’s past will make that difficult.

Downing Street is wargaming Johnson’s first phone call with Biden to help achieve the best personal and political connection.

It is understood the prime minister will ask Biden to join him in seeking a bold outcome to the UN climate summit the UK is hosting next year and to set up a “D10 coalition of democracies” at the G7 summit in June, which Johnson is to chair.

The PM will point out that both he and Biden have vowed to “build back better” after the Covid-19 crisis.

In a tweet last night Johnson congratulated Biden and his vice president-elect Kamala Harris for taking charge of “our most important ally” and called for them to work “closely together” on “climate change” as well as “trade and security”.

But this weekend, one of Biden’s campaign team accused Johnson of making “racist comments” in the past, compared Britain’s immigration policies to Trump’s and criticised British ministers’ stance towards Black Lives Matter.

“They do not think Boris Johnson is an ally,” the Democratic source said. “They think Britain is an ally. But there will be no special relationship with Boris Johnson.”

A senior US politician who is expected to take a job in the Biden administration recently told a British friend those views were shared by Harris. “If you think Joe hates him, you should hear Kamala,” the senior figure said.

Biden’s ire dates to comments Johnson made during the EU referendum, when he wrote that Obama’s decision to remove a bust of Winston Churchill from the Oval Office was a “symbol of the part-Kenyan president’s ancestral dislike of the British empire”.

Tommy Vietor, a former Obama press aide, responded to Johnson’s congratulatory tweet last night by calling him a “shapeshifting creep”, adding: “We will never forget your racist comments about Obama and slavish devotion to Trump.”

The source said: “Biden’s got a long memory and Boris is not in his good books. Biden and Obama are like family. Many of the people around Biden have been talking about Boris Johnson. The Kenyan remark has never gone away. They see Boris and [Dominic] Cummings like Trump and Bannon.”

Johnson’s relationship with Trump, and his past association with the alt-right strategist Steve Bannon, also make him an object of suspicion to Biden and to the Obama-era advisers who will form the core of his White House team, the campaign source said.

In fact, Cummings, Johnson’s most senior aide, has been withering in private about the president, telling colleagues months ago: “Trump is toxic” and urging ministers to keep their distance from him.

Aides said the mood in No 10 last week was one of satisfaction with the election.

But people around Biden, including Ben Rhodes, an Obama adviser now expected to take a national security role, have argued for Johnson to receive the cold shoulder.

In a TV address on Friday, Biden stressed tackling “systematic racism” as a priority. “Leaders who are not seen as allies on race, there will be big problems for those leaders,” the campaign insider said.

“He doesn’t want to work with people who project those views,” the aide said, and he was “shocked at the dismissiveness of black rights” after Dominic Raab, the foreign secretary, called Black Lives Matter protestors taking the knee, “a symbol of subjugation and subordination” and said that he would kneel only before the Queen or when proposing to his wife.

Britain’s hardline approach on immigration has also unnerved some of the team. “They see some of the policies that Priti Patel [the home secretary] is doing as similar to what Trump is doing on the border here,” the aide said.

The outspoken attack was not a sanctioned briefing against Johnson. But in laying bare the full extent of the Biden camp’s private views of the PM it reveals the mountain he has to climb to develop a close partnership with the new president.

Biden’s priorities on the world stage will be to reconnect with the EU and Nato and rejoin the Paris climate accord. That leaves little room for Britain’s hopes of securing a free trade deal.

There is hope in Downing Street that Biden, having failed to win a landslide and control the Senate, may need to be more conciliatory. “I do wonder if a not-so-strong result will make life easier,” said a cabinet source, who also conceded, however: “There’s a group of people in the Democratic camp who want a very public rejection of everything that Trump stood for. There is always the risk that that includes Boris.”

Johnson’s aides, aware of the tensions, stress common interests. One said: “The PM and Joe Biden share common ground and have a similar outlook on key issues like climate change and on our foreign policy priorities like strengthening Nato and our commitment to build back better from the pandemic.

“We are in the same place on Iran and Hong Kong. We have shared security goals in the Middle East and addressing the challenges posed by China. It is hard to think of any substantive differences.”

Knowing political relations could be strained, backroom staff, civil servants and military leaders are trying to cement relations with their opposite numbers in the US.

The key figure in No 10 is John Bew, Johnson’s foreign policy adviser, who spent time in Washington as Kissinger fellow at the Library of Congress.

“He’s part of the circle around Henry Kissinger, which includes Democrats and Republicans,” a colleague said. “He has close links to senior Democrats around Biden. He will be a pivotal figure. He’s just very well plugged in.”

Simon Case, the cabinet secretary, is also understood to be contacting Ron Klain, tipped to be chief of staff.

Intelligence chiefs will be urged to help persuade Biden that Britain is America’s key security ally. “Our best card is going to be security, defence and intelligence,” a diplomat said. “That’s the main thing we bring to the table.”

The British embassy in Washington, under ambassador Karen Pierce, has good relations with Tony Blinken, tipped as Biden’s secretary of state or national security adviser. They are also working on Larry Strickling, who is helping to develop Biden’s global policy.

Whitehall is also discussing plans to butter up Biden by offering him a state visit next year, tacked on to either the G7 or the climate summit. “There have been informal discussions,” a source said.

Tory circles are awash with speculation about who Biden will send as ambassador. One Conservative with a friend in Biden’s circles, claimed: “I have heard there is a possibility that Obama could be asked as a thank you.”The Biden source said they had not begun to think about that: “We are still working on the cabinet.”