The conventional wisdom a fortnight ago was that Boris Johnson wouldn’t survive the equivalent of a police interview under caution without a leadership challenge.

The first has duly happened but the second won’t – at least for as long as this crisis lasts.

News that the Prime Minister has filled in a form equivalent to an interview was buried last Wednesday beneath that of Russia’s impending invasion of Ukraine.

Sources in the Conservative Parliamentary Party confirm that there will be no challenge for the time being.

But I scarcely needed to make phone calls to confirm it.  Tory MPs can make strange judgement calls, but they’re not going to try to oust Johnson as a war in Europe worsens (at least, without some further unforeseen twist in the plot).

Our monthly survey reflects the change of mood.

In December, 55 per cent of our members’ panel said that the partygate story was not being overblown by the media. Forty-three per cent said that it was.

Last month, those percentages were roughly reversed (55 per cent said it was, 42 per cent that it wasn’t).

Now, just over a third say that partygate isn’t being so overblown, still a significant percentage – but outnumbered the best part of two to one by those who think it is.

The reason will partly be the fading of the story from the news and partly a certain sense of proportion.

Offensive as the flouting of lockdown rules at the heart of government may have been, it pales into insignificance compared to the reality of war in Europe – with Vladimir Putin putting his nuclear fleet on standby.

(Or at least it being indicated that he has.)

The protest by a fifth of the panel at our Next Tory Leader question in last month’s survey was a sign of the changing mood. They abstained rather than answer.

A question that follows is whether Johnson’s standing with voters is now set in stone.

James Johnson believes that voter views of the Prime Minister are settled (and that it’s highly unlikely he could win a majority again at a general election).

However, our columnist James Frayne thinks that there is a path to electoral recovery for the Conservative leader.

We will find out sooner or later who’s right, but the war in Ukraine is a tribute to the power of the unexpected in Westminster and Whitehall.

Johnson will have hoped in December 2019 that his governing mission was levelling up post-Brexit.

Instead, he has been faced within little more than two years of his near landslide victory at the polls first by pandemic, then by war.