Jeremy Hunt has implored British diplomats to continue ???speaking truth to power and standing up for British interests??? as the fallout from the resignation of the UK ambassador to Washington became a key battleground in the fight to succeed Theresa May.
In a message to all Foreign Office staff that will be seen as a coded rebuke to Boris Johnson, Hunt praised the departing ambassador, Sir Kim Darroch, hailing him and his diplomatic colleagues as ???the best of Britain???.
???The twin roles you perform of speaking truth to power and standing up for British interests have never been more vital,??? wrote Hunt, the foreign secretary, on Thursday. ???Please keep speaking up without fear or favour, remembering that the UK government alone will determine appointments based on our national interest alone.???
He added: ???I want you to know that you will always get all the support you need to carry out your vital work. I will ensure you get it.???
The reassuring missive was released after a day in which Johnson, the clear favourite to become the new prime minister, faced intense criticism from Conservative party colleagues over his perceived abandonment of Darroch.
At a Tory leadership hustings on Thursday evening, Johnson claimed he fully supports Darroch, despite his previous repeated public refusals to do so.
He told the audience: ???I rang Kim, I think yesterday, and said how much I regretted his resignation, which indeed I do. He, I think, was the victim of a very unpleasant stunt by somebody who tried to ??? and succeeded in ??? leaking his confidential diptels [diplomatic communications], which are intended to guide ministers and the government about his thoughts about what???s going on in Washington.
???And I think it was absolutely disgraceful that those diptels were leaked and I think it is vital ??? and as I said to Kim and I say to everybody ??? that all our civil servants, all great ambassadors such as Sir Kim, should feel free to speak without fear or favour to their political masters and then it is up to their political masters to decide what to do with it. And I think whoever leaked that, those diptels, deserves to be hunted down and prosecuted.???
Asked why he had been less willing to offer such clear public backing before Darroch felt moved to resign, Johnson said: ???I must say that I think there has certainly been an attempt to politicise this issue and to take the career prospects of Sir Kim and turn them into an issue in the Conservative leadership contest. I notice that.
???What I will say is that I don???t think that should happen and, as I said in the debate, I don???t think that issues of personnel in our civil service should become footballs in political conversations and just as the advice that civil servants give to ministers should be sacrosanct and ministers should not reveal it and should not betray it.???
In the background, there is also a fierce wrangle over who should replace Darroch in Washington and, crucially, whether the decision should be taken by May or her successor.
At an urgent Commons question about the affair, a series of Tory MPs lined up to criticise Johnson, who repeatedly refused to back Darroch after Trump insulted the ambassador in a series of tweets and said he would no longer deal with him.
One Conservative backbencher, David Morris, said Johnson, a former foreign secretary, should make a formal apology to parliament. ???Do you not feel that it is incumbent on every member of parliament in this place to back up our excellent diplomats and civil servants, and the honourable member for Uxbridge should come to the house and apologise???? he asked.
Adding to the likely discomfort of the Johnson camp, the Foreign Office minister tasked with responding to the urgent question was Sir Alan Duncan, who had the day before accused Johnson of throwing Darroch ???under the bus???.
Johnson has praised Darroch but stayed otherwise silent after declining several times during a Tory leadership TV debate on Tuesday night to offer support, something friends of Darroch said was a key element in the ambassador???s decision to resign the next day.
One of Johnson???s leading allies, the chief secretary to the Treasury, Liz Truss, spoke up for him on Thursday, telling a journalists??? lunch that while she did not like overseas leaders such as Trump ???slagging off??? the UK, she agreed with the US president???s criticism of May???s Brexit deal.
On the timing for appointing a new ambassador, Truss predicted this would take months and so it would be a job for the next prime minister.
On Thursday evening, Johnson talked up the importance of the maintaining a working relationship with Washington, but insisted that there were circumstances in which he would publicly criticise Trump.
He pointed to his response to Trump???s claim in 2015 that some parts of London were ???so radicalised that police are afraid for their own lives???. At the time, Johnson noted, he had replied that the ???only reason I wouldn???t go to some parts of New York is the real risk of meeting Donald Trump???.
That came after other Tories had been openly critical of him. During the urgent question, one Conservative MP, Roger Gale, told the Commons: ???The failure of the former foreign secretary to leap to the defence of Sir Kim shows a lack of leadership that is lamentable.???
Tom Tugendhat, who chairs the Commons foreign affairs committee, was less direct, but made his feelings known, saying the loss of Darroch after Trump???s comments amounted to the UK being bullied.
Tugendhat said the government should ???always stand up for those we send abroad, military or civilian, and will back them to the point that is necessary in the interests of the British people, and no one else???.
The only support for Johnson in parliament came from the veteran Tory backbencher Peter Bone, who said: ???The attacking of colleagues is completely wrong and people should be ashamed of themselves when they???ve done that.???
The urgent question was tabled by Labour???s Pat McFadden, who said the decision of Darroch to resign, despite having the full support of Theresa May and her cabinet, was ???a dark moment for our democracy and for the standing of the United Kingdom???.
McFadden said Johnson???s lack of support for the envoy was ???an appalling abandonment of someone in the firing line???. He added: ???Real leaders protect their people, they don???t throw them to the wolves because they can sniff a prize for themselves. His actions are a chilling warning of what is to come if he becomes prime minister.???
Duncan said he would not be responding to such views on Johnson: ???I hope the house will understand if I hold back today from making any further comment on the right honourable friend the member for Uxbridge. I said enough yesterday to make my position entirely clear.???
Duncan nonetheless managed to reiterate his condemnation of Johnson several times in ways varying from the coded to the open. Responding to one question, he replied: ???It is everyone???s duty, and everyone in this house???s duty, to defend our ambassadors. They are our ambassadors doing our duty. If they do something terribly wrong or break all the rules, that???s altogether different.???
Duncan later drew laughter after the Liberal Democrat deputy leader, Jo Swinson, cited his description of Johnson???s actions as ???the behaviour of an utter wimp???. ???I seem to recall that was one of the kinder words I used yesterday,??? he told MPs, adding: ???I think what I would rather do is concentrate on the specific details of the question put, the merits of Sir Kim Darroch rather than the ??? merits of anyone else.???
Predictions about who will fill the role have already begun, with names mentioned including Sir Mark Sedwill, the head of the civil service.
The appointment would help smooth the return to the cabinet of Gavin Williamson under Johnson, whose campaign he has helped run. Sedwill played a leading role in Williamson???s dismissal as defence secretary in May after an inquiry found he had leaked information about the role of Huawei in the UK???s 5G network.
Political figures named as possible successor include the former Tory leader Iain Duncan Smith, the international trade secretary Liam Fox, and the chancellor-turned man-of-many-jobs George Osborne.