Boris Johnson faced a backlash after refusing to guarantee that he would keep the UK’s ambassador to Washington in post following the leak of sensitive diplomatic messages about Donald Trump.
The former foreign secretary sidestepped questions over whether he would allow Sir Kim Darroch to remain in the job until he is due to retire later this year, insisting it was “vital” the civil service is not politicised.
The leak of the diplomatic dispatches has soured relations with the Trump administration and prompted a Twitter tirade from the US president, who described Sir Kim as a “pompous fool” and a “very stupid guy” who had been foisted on the US.
During a head-to-head debate with Conservative Party leadership rival Jeremy Hunt, Mr Johnson declined to offer a guarantee that Sir Kim would continue in post.
Mr Johnson said: “I think it is absolutely vital that the advice that civil servants give to ministers should not be leaked by ministers and should not be commented on by ministers if civil servants are going to feel free to give that advice with the impartiality that they want.”
But he refused to say whether he would keep Sir Kim in post, and instead he told the ITV debate: “It is vital that our civil service is not politicised by ministers leaking what they say. Whoever leaked that deserves to be eviscerated.”
Former prime minister Sir John Major warned that if a senior diplomat was “thrown to the wolves” it would damage the relationship between an incoming prime minister and the civil service.
“We really cannot have our ambassadors chosen by the host government, however eminent those host governments may be,” Sir John, who is backing Mr Hunt in the leadership race, told BBC Radio 4’s Today programme.
Pointing out that “loyalty is a two-way street”, Sir John said: “I do not think that is good for the morale of the civil service and I do not think anybody who does that will endear themselves in obtaining the loyalty of the civil service in future.”
Foreign Office minister Sir Alan Duncan, whose brief includes the United States, said he was “severely disappointed that Boris Johnson appears unwilling to stand up for our ambassador to the US, our PM or our country”.
Sir Alan, another Hunt supporter, said Mr Johnson was an “utter wimp when the crunch comes when he should be making a stand”.
Labour former foreign secretary David Miliband gave his support to Sir Kim as a “true public servant”.
Former ambassador to France Lord Ricketts echoed that view and added “I wish Boris Johnson could have brought himself to say the same.”
Downing Street has backed Sir Kim after Mr Trump warned on Monday the White House would have nothing more to do with him.
The first indication of the rift became evident when the ambassador was “uninvited” to a White House dinner on Monday evening, held in honour of the Emir of Qatar.
Sir Kim was also not attending a meeting between Ivanka Trump and International Trade Secretary Liam Fox in Washington.
In a further sign of complications in the special relationship, an expected meeting between Dr Fox and US commerce secretary Wilbur Ross failed to take place – officially due to “diary clashes”.
Meanwhile Theresa May posted a Twitter message of herself with Cindy McCain, the widow of Mr Trump’s political rival John McCain.
She had been in Downing Street for talks on tackling modern slavery.
Health Secretary Matt Hancock, who is supporting Mr Johnson’s leadership bid, said Sir Kim is an “incredible public servant” who was “doing his job in writing those memos”.
But he told Today: “We also have to repair this relationship with the White House and with the US government.
“It is our most important diplomatic relationship. Whoever is the president of the United States, we have to have a strong relationship with them.”
A formal civil service leak inquiry has been launched into how Sir Kim’s messages were disclosed to the Mail on Sunday, but MPs called for the police to investigate.
The Foreign Affairs Committee, which will hear from senior Foreign Office mandarin Sir Simon McDonald on Wednesday, has written to the Prime Minister, Foreign Secretary and Metropolitan Police Commissioner Cressida Dick about the leak.
In his letter to Scotland Yard calling for a police investigation, committee chairman Tom Tugendhat said: “This appears to be a serious criminal act.”