Once the emails leaked, nothing could have been done to save Sir Kim Darroch (Image: GETTY)
According to Emily Thornberry, Boris Johnson's failure to back Sir Kim was "the most craven and despicable act of cowardice I have seen from any candidate for public office". Steady on. Even if you did think that Boris should have thrown his weight behind our man in Washington, his refusal to do so would surely not even rank as the biggest act of political cowardice of the day. That title would surely belong to Jeremy Corbyn for refusing interviews to respond to Panorama's expose of anti-Semitism in Labour and his staff's attempt to rubbish the documentarymakers instead. But there is really very little that Boris - or anyone - could have done to save Darroch. There was nothing wrong with him sending a frank assessment of Donald Trump's character and ability to govern in a private memo to London. Indeed, it is part of an ambassador's job to provide such opinions.
Yet someone in the very small circle of ministers, civil servants and diplomats who would have seen the memo has decided to leak its contents. Once that happened it became impossible for Darroch to continue in his job.
Some people - Theresa May and Jeremy Hunt included - have tried to assert that it is a kind of feeble surrender to Donald Trump to withdraw Darroch from Washington.
We can't possibly allow a foreign government to choose whom we send to represent us in their country, they say.
Yet ambassadors can only function if they have a positive working relationship with the government of the country in which they are working.
An ambassador is a guest at a foreign court, not a negotiator sent to meet opponents in order to get a good deal.
Emily Thornberry, shadow foreign secretary, was outraged at Boris's refusal to back Sir Kim (Image: GETTY)
It is not his or her job to be tough and unyielding, but to snuggle up to the foreign government and act as an intermediary when delicate protests and apologies have to be passed to and fro.
At all times an ambassador should be seeking to calm down tensions created by the more robust political exchanges going on.
Moreover, it is simply not