Britain is going to need a new Prime Minister, and soon. Everyone paying attention knows it, even if a few people near power don’t want to admit it for fear of the implications. There is far too much buggering about going on. The Prime Minister’s authority is gone completely and the government is only functioning after a fashion. Of course she is being painted, unfairly, as an uncaring person. The descriptions from clergy of the private meeting she had in Number 10 Downing Street with those affected by the fire show that. She was deeply moved and listened and promised action.

But there is simply no appetite for her to continue in office other than on the short-term basis. If Theresa May can get through to the summer recess then her patriotic work will be done and someone else must step in. How – as they used to say – is the Queen’s government to be carried on?

In an effort to find out I’ve spent part of today ringing round – I know how to have fun – and the Tory mood among ministers, MPs and grandees seems pretty settled that it’s over but no-one will say so publicly. The most charitable interpretation, as Tim Shipman reports in the Sunday Times, is that Theresa May has ten days in which to somehow recover the situation. But a lot of senior Tories seem to have moved on, seeing that ten day spell in terms of time to organise a replacement. The mainstream position of a week ago, that a change of leader is undesirable because May is good at being Prime Minister and it might all calm down over the summer, has been rendered inoperable by Grenfell and the perceived failings in the Prime Minister’s initial response.

So, who becomes the next Tory leader?

Here I should give you an intelligence analysis or a vague assessment, hedging my bets and saying that it certainly promises to be an interesting race and watch this space and all that. I’m not going to bother doing that this time. Cards on table. The Tory party is the largest party. It needs a replacement Prime Minister, and damn quick, preferably without a messy leadership contest. That does not mean there must be a general election to follow, merely that someone could try to hold together a minority government for two to three years and sort out Brexit.

There seems, to me, to be only one sensible option. That is David Davis, who is Brexit Secretary.

Davis is, I’m told, in the May-must-stay-have-you-all-lost-your-minds? camp. But then in 1940 Churchill was in the Chamberlain must stay camp after the military disaster of the Norway campaign (which was partly Churchill’s fault). Nevertheless, Churchill shortly afterwards became Prime Minister, thank goodness. Cometh the hour, and so on.

How did I arrive at this view? In a calm frame of mind run your finger down a list of the cabinet, ruling out in the first sweep much more than half on either the “who dat?” basis or a judgement that they are good ministers but not made for an emergency in prime-time.

Then consider what’s left.

Chancellor Philip Hammond? Anything is possible, we have learnt in the last few years, but for all his talents with a spreadsheet does Philip Hammond have a story to tell, a connection to make, a rallying speech to make, the inherent leadership thing? Nope.

Defence Secretary Sir Michael Fallon? Talented, tough, but can’t see him matching the Grenfell meets Brexit moment.

Jeremy Hunt? No.

Amber Rudd? A serious figure with much to offer. Could have led, if her majority in Hastings was not now so tiny that she is on course to lose her seat next time. Not a good look.

And then there is… Boris.

I never leave a rare encounter with the Foreign Secretary without a smile on my face. Indeed, his best chance was always to be the post-Brexit “put a smile on their face” leader in about 2022, echoing the spirit of London 2012 (remember that?). The simple truth is that Boris worries the country and the Tory party way too much, particularly at a juncture as sensitive as this. There are too many stories. There are too many examples of his administrative shortcomings. I haven’t even mentioned what his enemies in the Tory tribe say about him.

On that score, David Davis himself is not lacking in flaws. I was one of those who criticised him sharply for the daft decision to hold a by-election almost a decade ago, when he lost his shadow cabinet position just at the moment when he could have made a difference inside the Cameroon tent.

Against that, he is a grown-up, who grew up on a council estate as the son of single-mother who later remarried. A grammar school education culminated in his not doing well enough in his exams. He took a job and joined the TA and retook his exams, going on to earn three degrees at Warwick, the London Business School and Harvard. Following a successful business career he got into parliament. Davis is a toughie, who has known setbacks. He is certainly not someone who would be nervous about talking to angry or grieving people with genuine grievances on a council state or anywhere else. He can compromise sensibly on Brexit too if the EU seeks compromise.

The next week may decide a lot. David Davis begins the Brexit talks tomorrow and if they start badly then these calculations I’ve sketched out could prove flawed.

But if Davis has a relatively good week and May has a bad week, DD may be Prime Minister before the month is out. He is by far their best option.