UK's new ambassador to US named following leaked memos scandal

Popular career diplomat Dame Karen Pierce has been named Britain's new ambassador to the US, becoming the first woman to hold the top overseas posting.

She will take over a job vacated prematurely by Sir Kim Darroch , who resigned last summer after confidential messages offering an unflattering view of President Donald Trump were leaked.

The revelations prompted a furious backlash from Mr Trump, who called Britain's man in Washington a "pompous fool".

Boris Johnson - who knows and likes Dame Karen - signed off on the appointment and took to twitter to praise her.

"Karen Pierce is an outstanding and accomplished diplomat and I can think of no better person to drive forward our hugely important relationship with the United States at this time," he wrote.

"I'm delighted she'll be representing us in Washington."

Dame Karen, known as a tough negotiator, may have her work cut out to mend fences after the row sparked by the Darroch leaks.

She will be all too aware that this is a critical time in US-UK relations with the prime minister seeking to seal a new post-Brexit trade deal.

In a statement, she said: "I am honoured to have been asked to represent the UK in the US. I think it is the UK's single most important relationship. There is a deep bond between Britain and the US, built on many pillars.

"We have a fantastic cross-government team across the US and I look forward to working with them to strengthen and even further deepen the special relationship between our two countries and peoples."

Dame Karen is currently serving as the UK's permanent representative to the United Nations in New York, a position she has held since March 2018.

But she is well known to the prime minister, having served as chief operating officer at the Foreign and Commonwealth from 2016 when he was foreign secretary.

It is understood that the two have a good relationship.

The position of ambassador to Washington is highly coveted - typically given to the Foreign Office's most experienced diplomats.

However, speculation had mounted after the resignation of Sir Kim that his replacement might be a political appointment who had been a strong advocate of Brexit.

Mr Trump had even suggested Nigel Farage, a personal friend and the leader of the Brexit Party, would be a worthy choice.

There had also been rumours Sir Mark Sedwill, a diplomat before joining the Home Office and then taking over as cabinet secretary and national security adviser, was set to be moved to Washington as ambassador.

Source said, though, that he has a good working relationship with Mr Johnson and the prime minister's top adviser, Dominic Cummings, meaning that he is set to stay in his current post.

The choice of Dame Karen is a more traditional selection, drawing on the Foreign Office's pool of talent.

She joined the department in 1981 and has enjoyed postings as far afield as Tokyo, the Balkans and Afghanistan.

The diplomat is hugely popular within the foreign office, with colleagues hugely supporting of appointment.

Dame Karen will begin her new mission after obtaining the United States' formal agreement.