This has to be one of the darkest days in the recent history of the civil service, at the end of what has been a particularly unpleasant few months.

The deliberate leaking of some of the most confidential communiques this government receives from its diplomatic service was clearly designed to undermine Her Majesty’s Ambassador to the United States. Why and who is yet to be determined. Whatever Machiavellian plot this serves, it was deemed worthy of the cost of damaging not only the relationship with our closest ally, but the reputation of the British government.

Like the targeting of Olly Robbins and Sir Mark Sedwill, these selective leaks are increasingly becoming the modus operandi of a number of politicians (or, more frequently, those around them, to provide that all-important plausible deniability).

Whatever short-term gain they believe they’re achieving, it is being exacted at some considerable long-term cost. It has been a feature of May’s premiership up until now to stay silent as the attack dogs in the ERG castigate the civil service as a ‘remainder clique’, and target individuals who they dub ‘treasonous’. Ironically, it is in the dying days of her time in office that May chose to publicly defend a civil servant who was doing exactly what we have asked of him: providing this country with his analysis of a foreign government. The Prime Minister and Foreign Secretary were quick to make clear that, whilst they disagreed with the analysis, they would defend the right of the Ambassador to provide it.

It was not, however, the lack of political support from the Foreign Secretary that made Sir Kim’s position untenable. It was the equivocation and bluster that we have come to expect from the very man who Sir Kim previously served, and who will undoubtedly have been aware of the nature of that advice, if not the actual communiques themselves.

When Boris, pressed several times, refused to provide support for Sir Kim, it was clear to all that the Ambassador’s time would be limited under a Johnson administration. Matt Hancock’s parroting of the same line this morning was only notable for his claim, in the same breath, that civil servants should still feel confident providing advice without fear or favour. Favour is one thing, but fear is another. Sir Kim is only the latest senior civil servant to be targeted or driven from their role.

Public servants, who have dedicated a lifetime to serving governments of different stripes, and have committed their careers to serving the national interest, are now being targeted routinely when they do not  serve a narrow political agenda. The cause of this is not only Brexit, though that has been the lightning rod for many of these attacks. On the left, tired old tropes of establishment plots abound and there is a similarly muted response to attacks, even when it would appear on the face of it to be a political open goal to defend public servants.

The events of the last few days do, however, feel like they represent a shifting of the tectonic plates. The age old compact between civil servants and ministers – where their impartiality and professionalism would be defended to protect the very principles that make for effective government – was intact, if under strain. Now, the orchestrated ousting of one of the most respected and senior diplomats in the world will send a clear message to all civil servants that they are expendable. That loyalty is not a two-way street. That ministers continue to expect them to serve – to provide advice and to deliver the government’s will, but they will not be protected if it is deemed politically inconvenient.

We are already seeing some of the most senior civil servants involved in the maelstrom of Brexit take matters into their own hands. In the last few months we have lost the permanent secretary at DExEU, the director who was leading on no-deal preparation, the director general of border coordination and the prime minister’s Europe advisor, who was the lead negotiator. The events of this week will, I am sure, only serve to hasten the departure of others.

And what of those who remain? Despite the protestations of ministers today that it is a safe environment, does anyone really imagine that a civil servant faced with a request for advice on a controversial issue, or a diplomat asked to provide a sensitive critique of a close ally, will not think twice about the nature and frankness of that advice?

It is not only the UK’s reputation that has been damaged by these events, but our ability to govern effectively. Only time will tell whether the damage is irreparable.

Dave Penman is general secretary of FDA, the civil service union