Diplomats are hoping that the arrival in the White House of Joe Biden will usher in a more predictable era in the US-UK “special relationship” after the turbulent presidency of Donald Trump.

The swearing-in of Mr Biden as the 46th president may raise some uncomfortable questions for Boris Johnson, given his perceived closeness to his predecessor.

But Britain’s ambassador to the US said the overwhelming mood among diplomats in Washington was one of relief that order had been restored after the dramatic storming of the Capitol on January 6 by outraged Trump supporters.

“I think the whole of the diplomatic corps is very pleased to see American democracy come out on top,” Dame Karen Pierce told the BBC Radio 4 programme.

Dame Karen sought to play down claims that Mr Johnson may face a cool reception in the new White House after Mr Trump once hailed him as “Britain’s Trump”.

“Whatever President Trump said about the Prime Minister, I don’t think that’s the image people have here of the Prime Minister, to be absolutely honest,” she said.

Nevertheless, Mr Johnson is regarded with deep suspicion by some senior Democrats around Mr Biden who – unlike Mr Trump – was no fan of Brexit.

Many were offended by his sideswipe at the “part-Kenyan” Barack Obama during the 2016 EU referendum campaign, while Mr Biden once described him as a “physical and emotional clone” of Mr Trump.

But Dame Karen argued that the new president’s commitment to a rules-based international order offered a way forward for future co-operation in the years ahead.

She said that Mr Biden had already signalled his intent to rejoin the Paris accord on climate change and the Iran nuclear deal – both of which were abandoned by Mr Trump.

And with Britain in the chair for the upcoming G7 summit in Cornwall and the Cop26 international climate change conference in Glasgow, there was significant scope to work together on issues of mutual interest.

“I think everybody is looking forward to a period of co-operation working with allies,” she said.

“We want to be able to use our G7 presidency to work with President Biden and Vice-President (Kamala) Harris, and to really get the Covid economic recovery on track, bolstering economic resilience and trying to set things on a recovery path that really reinforces open markets, democratic values, building back better.”

Her words were echoed by former prime minister Theresa May who had a difficult relationship with Mr Trump during her time in office.

Writing in the Daily Mail, she said that while Mr Biden would have his own agenda in pursuit of the US national interest, he would be a “more predictable and reliable partner” than his mercurial predecessor.

“When a British prime minister walks out for a joint press conference with the world’s media unsure if the United States president standing next to her will agree that Nato is a bulwark of our collective defence, you know you are living in extraordinary times,” she said of Mr Trump.

In the longer term though, it is Brexit that may present the greatest challenge for the special relationship, with some observers believing the new administration will look increasingly towards Berlin and Paris now Britain is outside the EU.

Quentin Peel, associate fellow on the Chatham House international affairs think tank’s Europe programme, said: “Britain was seen in Washington as a very useful link to the European Union and therefore a binding factor.

“I think the fact that Britain is no longer a very useful link to the European Union does matter and will weaken the relationship.”

Nevertheless, traditional military and intelligence-sharing links are likely to remain strong, and it will not have gone unnoticed in Washington that Mr Johnson announced a big increase in defence spending at a time when other Nato allies are failing to meet their commitments.

But with some tricky waters to navigate first, the coming weeks and months may be crucial in shaping the way the relationship plays out over the years ahead.