Sir Kim Darroch has resigned as UK ambassador to the US, as a row over leaked emails critical of President Trump’s administration escalates.
The US president had branded him “a very stupid guy” after emails emerged where the ambassador had called his administration “clumsy and inept”.
Theresa May said Sir Kim’s departure was “a matter of deep regret”.
He said he wanted to put an end to speculation about his role and the leak had made it “impossible” to continue.
In a letter to the Foreign Office, Sir Kim said: “Although my posting is not due to end until the end of this year, I believe in the current circumstances the responsible course is to allow the appointment of a new ambassador.”
The leak was described as “malicious” by Sir Simon McDonald, permanent under secretary and head of the diplomatic service, who told Sir Kim: “You are the best of us.”
He told the Commons’ foreign affairs committee it was the first time in his career that a head of state had refused to work with a British ambassador, after President Trump said the US would “no longer deal with” Sir Kim.
Mrs May said he had had the full backing of the cabinet and had given a “lifetime of service” to the UK, for which he was owed an “enormous debt of gratitude”.
“Good government depends on public servants being able to give full and frank advice”, she said.
She spoke of the importance of “defending our values and principles particularly when they are under pressure”.
His resignation has prompted widespread support for Sir Kim while some have questioned Tory frontrunner Boris Johnson’s stance.
Mr Johnson had refused to say, during the Tory leadership debate on Tuesday night, whether he would keep Sir Kim in post if he became prime minister.
Following Sir Kim’s resignation, he said he was “a superb diplomat” and whoever was responsible for the leak “has done a grave disservice to our civil servants”.
Asked why he was not more supportive of Sir Kim, he said it was “wrong to drag civil servants into the political arena”.
Europe Minister Sir Alan Duncan said it was “contemptible negligence” not to support Sir Kim.
“He’s basically thrown this fantastic diplomat under a bus to serve his own personal interests,” he said.
Tory MP and chairman of the Commons’ foreign affairs committee Tom Tugendhat said in a tweet: “Leaders stand up for their men. They encourage them to try and defend them when they fail.”
However, Sir Michael Fallon – a supporter of Mr Johnson – said the Tory leadership hopeful had made it “very clear that the relationship with the United States is what comes first”.
Fellow Tory leadership candidate and Foreign Secretary Jeremy Hunt said he “profoundly” regretted the “outrageous” leak that led to Sir Kim’s departure. “It should never have come to this”, he added.
BBC political editor Laura Kuenssberg said: “Failing to back Darroch last night was the first major act of the still hypothetical Johnson premiership that led to his resignation.”
President Trump could well wake up this morning thinking he has the power to veto who the UK has as it’s ambassador.
It wasn’t his more colourful remarks on Twitter that really ended Sir Kim’s time, but Mr Trump’s public announcement that he would no longer work with him.
The effects of that were felt immediately. There was a banquet that Sir Kim was immediately dis-invited from. Next, he couldn’t attend an event with minister Liam Fox.
It was clear he was being frozen out and for an ambassador access is everything. Without it, it’s impossible to do the job.
More broadly, it’s like this… There’s never been parity in the special relationship between the UK and US – it’s never been a relationship of equals but right now it seems particular lopsided.
The US knows that Britain is fairly isolated right now internationally and needs the US more than ever. Donald Trump has wielded that power mercilessly in this row.
In the Commons, Labour leader Jeremy Corbyn described Mr Trump’s comments about Sir Kim as “beyond unfair and wrong.”
In the emails leaked to the Mail on Sunday, Sir Kim said: “We don’t really believe this administration is going to become substantially more normal; less dysfunctional; less unpredictable; less faction-riven; less diplomatically clumsy and inept.”
The emails, dating from 2017, said rumours of “infighting and chaos” in the White House were mostly true.
Sir Kim thanked those who had offered their support, both in the UK and the US during a “difficult few days”, adding that it had “brought home to me the depth of friendship and close ties between our two countries”.
The government has opened an internal inquiry into the publication of the memos.
Police have been urged to open a criminal investigation into the leak.
Who is Sir Kim Darroch?
Born in South Stanley, County Durham, in 1954, Sir Kim attended Durham University where he read zoology.
During a 42-year diplomatic career, he has specialised in national security issues and European Union policy.
In 2007, Sir Kim served in Brussels as the UK permanent representative to the EU.
He was the prime minister’s national security adviser between 2012 and 2015, dealing with issues such as the rise of the Islamic State group in Iraq and Syria, Russian annexation of Crimea, the nuclear threat from Iran and the collapse of government authority in Libya.
He became ambassador to the US in January 2016, a year before Donald Trump’s presidential inauguration.