Senior civil servants have warned of a “disturbing pattern” of top officials being forced out of their jobs following the resignation of Sir Kim Darroch as ambassador to the United States.
Dave Penman, general secretary of the FDA union representing senior officials, said ministers were failing to stand up to attacks from politicians and sections of the media.
Sir Kim said his position had become “impossible” following the leak of diplomatic cables in which he was highly critical of the Trump White House.
Across Westminster there was concern that his position had been further undermined after Boris Johnson, the front runner to succeed Theresa May as prime minister, repeatedly refused to defend him in a televised leadership debate on Tuesday.
It comes ahead of the expected departure of Mrs May’s chief Brexit negotiator, Olly Robbins, following repeated attacks by Tory Brexiteers.
Mr Penman said Sir Kim had been placed in an “impossible situation” by the failure of Mr Johnson and his supporters to offer their “unequivocal support”.
“Johnson and his allies have sent the clearest signal possible to Sir Kim, the diplomatic corps, the wider civil service and, unfortunately, to foreign governments: that civil servants’ professional, impartial advice is needed, but they are ultimately expendable if it proves politically expedient,” he said.
“We are witnessing a disturbing pattern emerge, where the brightest and best civil servants are being forced out of their jobs due to relentless attacks from politicians and some sections of the media – escalating to death threats and threats against their families in some instances.
“It is the job of ministers and indeed the Prime Minister to defend their civil servants from this kind of abuse.
“But time and time again, they are choosing to stay silent and as a result they have created an environment where the targeting of individuals or undermining of the service as a whole has become routine.”
International Trade Secretary Liam Fox said the case was highly damaging to British diplomacy and that it was essential to find out who was responsible for the leak.
“Somebody has, for whatever malicious reasons, sought to either damage the US-UK relationship or indeed Sir Kim personally,” he said.
“It’s important that our ambassadors are able to write frankly to politicians. If they have to do so worrying about how it might look in a newspaper it will represent a fundamental change in how our diplomatic system operates.
“I’m afraid the world has looked at this episode and they will have seen that there has been, in this case, what I would describe as an unprofessional, unethical and unpatriotic lapse in the usual standards we have come to expect in this country.”
In contrast, Brexit Party leader Nigel Farage – an enthusiastic cheerleader for Donald Trump – hailed his departure as the “right decision”.
“Time (to) put in a non-Remainer who wants a trade deal with America,” he tweeted.
However, Republican senator Lindsey Graham, an ally of Mr Trump, said he believed Sir Kim had had a “raw deal” from the press, with “selective” coverage of his cables.
“Kim Darroch did an outstanding job as ambassador and sorry to see he has resigned his post,” he tweeted.
“Ambassador Darroch always understood the strength of President Trump and referred to him as the ‘Terminator’ who is indestructible and will most likely be re-elected.”