Why Theresa May probably has a year left as PM

So here is what I assume MPs and Tory ministers will agree on the longevity of Theresa May as PM - although I don't suppose much of any of this will be officially confirmed.

If the DUP agree not to bring the government down for at least a year, through a confidence-and-supply arrangement, then that gives the Tory party a year for its candidates to prepare where they would wish to take their party.

There would then be a leadership election a year from now - and culminate in a choice of a new Tory leader and prime minister at the end of the summer of 2018, allowing the new leader to be installed in time for party conference in the autumn.

There would be three leading candidates: David Davis, Boris Johnson and Amber Rudd. Others however are likely to emerge in the coming months.

Cabinet heavyweights Amber Rudd, Boris Johnson and David Davis are touted as candidates to replace Theresa May. Credit: PA

Someone now considered obscure and a long-odds bet, even someone not currently in the cabinet, could for example outline a vision for how to reconnect the Tory party with younger voters or at least soften their disgust with the government - an important if Herculean challenge - which could transform him or her into a credible candidate.

Remember that Cameron and Blair became the blindingly obvious saviours of their parties in a sentiment shift which was invisible till it became an earthquake.

Anyway, as I understand it, a year's extension of May's rule is what the cooler heads at the top of the government see as their best hope of turning last week's electoral setback into a plausible basis to fight a General Election in either the autumn of 2018 or the spring of 2019.

By then the shape of a Brexit deal - if such there be - should be clearer.

DUP leader Arlene Foster has already dented Theresa May's hopes of a more formal coalition. Credit: PA

And May's government will have chugged along legislating in a fairly minimal way, because as I said on Sunday it will have to ditch most of the contentious items in the manifesto to avoid too many embarrassing Commons defeats (the DUP won't back the end of the triple lock on pensions, the means testing of winter fuel payments, elderly people paying more for social care and so on, and even with the possible support of the DUP there's no majority in the Commons for grammar schools).

To state the obvious, it was a bit of a body blow to the PM on Saturday when the DUP refused to countenance a more formal coalition - which would have been a much more stable basis on which to govern than a confidence-and-supply deal (it means no more than that the DUP won't bring the government down for a period and provides plenty of latitude for it to disagree with the government).

Of course the Tories may not have the luxury of such an orderly transition.

There may be kamikaze rebellions by groups of Tory MPs.

Boris Johnson's supporters may seek to hasten their man's attempt to enter Number 10. Credit: PA

For all of Boris's Churchillian demands for the party to fall in behind Theresa today, his enthusiastic lieutenants may not be able to curb their enthusiasm for his cause for a whole 12 months - and could trigger civil war in the party.

The deal with the DUP may never actually be consummated and could collapse.

So for the government - and I guess for us too - it will be a hairy 12 months.

But there is probably a better than evens chance that May has a year left of her time in office, and a year to rebuild her battered reputation.