Sir Kim Darroch, the British Ambassador to the U.S. described by President Trump as “a very stupid guy”,  has resigned his post. The final straw, he has claimed, was watching future Prime Minister Boris Johnson repeatedly failing to support him last night in a TV debate.

This is great news for a number of reasons.

First, it means that Britain is now free to appoint a replacement ambassador prepared to nurture the Special Relationship rather than undermine it with snarky memos dissing President Trump.

Second, it has quite ruined the day of Britain’s liberal elite – aka the Wankerati. Anti-Brexit, anti-Trump, pro-climate-change hysteria, Darroch was very much their man in Washington. One dripping wet Times columnist has even gone so far as to suggest – without irony – that Darroch’s departure is a national humiliation to rank with the Suez crisis.

Third – and most importantly – it’s the first glint of steel we have seen from Boris Johnson and encouragingly suggests that Britain is about to get a Conservative prime minister very different from his recent predecessors.

The situation is summed up well here in the Spectator by Robert Peston, in a piece headlined ‘Why Boris Johnson failed to defend Kim Darroch.’

According to those closest to him, this isn’t just kowtowing to the most powerful person in the world – Trump – in order to borrow some of his status. It’s to do the opposite of what many of his critics allege is proper; it is deliberately to put Whitehall on warning that it’s Johnson’s way or none.

Yes, exactly. For years, one of the main obstacles holding back the Conservatives in government from doing anything remotely conservative has been the Civil Service. Ever since it got politicised under Tony Blair, the Civil Service – shamelessly pro-EU, aggressively politically correct, relentlessly left-wing – has done everything it possibly can to undermine Brexit and to prevent the kind of smaller-government, lower-tax, populist revolution currently being enjoyed in the U.S.

If Boris Johnson is to keep his promise to deliver Brexit come what may by October 31st, one of his first jobs will be to put the Civil Service back in its box.

The auto-defenestration of Darroch will, as Peston goes on to explain, serve as an excellent example ‘pour encourager les autres.’

The point is that there are many Brexiters in the Johnson fan club who see civil servants as the vandals and destroyers of Brexit. They are viewed as the Remainy enemy within, who captured Theresa May and shoved her off the true path to the sunny uplands outside the EU.

So Darroch’s perceived attack on Johnson’s Brexity friend in the White House is paradoxically useful to Johnson. It gives him a way of signalling to senior mandarins that if they show anything but Stakhanovite commitment to extracting Britain from the EU they can expect early retirement at best or transfer to the salt mines in the departments of transport, or work and pensions at worst.

That slightly sneering tone you detect in Peston’s analysis, by the way, is because he leftist and a Remainer who can’t help himself. It certainly doesn’t mean in any way that his scorn is justified.

On the contrary, through the cunning expedient of simply not saying anything positive about a rubbish ambassador who probably despises him and who was doomed anyway, Boris Johnson has played a blinder.

To President Trump, he has signalled: I’m your new best mate.

To his Conservative party backers (most of whom are Brexiteers), he has signalled: I’m not going to sell you out.

To the Civil Service, he has signalled: you aren’t the masters now.

To Britain at large, he has signalled: there’s a new sheriff in town and you’re going to be seeing a few changes, some of which you may not like, but tough – I’m wearing the shiny star badge, not you.

Yes, of course it’s very early days. Boris isn’t even in Number 10, yet. He’s a terrible flip-flopper who may yet revert to type.

But on first glance, this all looks very, very promising.

As for Sir Kim Darroch, perhaps it’s time to find him a posting where he’s less likely to damage the Special Relationship. I’m told the British consulate in Ouagadougou is looking particularly lovely at this time of year.