What is Theresa May's cunning plan for Brexit (and her survival)?

Does Theresa May have a way of appeasing all parties on Brexit? Credit: PA

After the tumultuous events of the last few days, you might be tempted to believe that the PM's planning horizon is roughly six hours - because since she agreed her Brexit plan at Chequers, she's been clinging to office by the tips of her exquisitely manicured fingers.

That is certainly the view of one senior Tory, who told me "it's all about numbers and letters to Graham Brady [letters calling for a change of leadership]; their sole focus is survival, not doing the right thing".

That MP is not a lone voice. But although the PM seems more at the mercy of events - and her own divided party - than any PM in decades, she does have a route map.

This is it.

She hopes and expects that the rest of the EU 27 will have agreed her third-way Brexit plan by the late autumn.

And yes of course that cannot remotely be taken for granted - for all the reasons I've been banging on about for days (the EU thinks Mogg's amendments blow up both the crucial Northern Ireland backstop, without which no deal of any sort is possible, and May's complicated customs plan, the Facilitated Customs Arrangement).

But let's make the challenging assumption that Angela Merkel has the will and authority to force agreement around some kind of compromise Brexit on 26 other EU governments that is not a million miles from May's white-paper plan (this is a thought experiment, not a forecast).

According to those close to May, and her thinking, the PM would then expect that all but 20 of her MPs would vote for that compromise - and that opposition from roughly 20 of the European Research Group's Brexit ultras would be offset by support from rebellious Labour MPs also of a Brexity bent.

Mrs May was grilled by the Commons Liaison Committee on Brexit. Credit: PA

Before continuing, we should pause and admire the delicious paradox here.

May is assuming she would be rescued from the opposition of the Moggs and Fyshes by support from the Hoeys and Manns - the first group of Tories pulling the rug because they would rather have no deal than what they see as a treacherous deal, and the latter collection of Labour members preferring any deal to their feared Remainer backsliding.

If you think this logic is dodgy, you may not be alone.

May is also assuming that the Soubrys, Grieves, Morgans and Hammonds will always back her, if the inescapable alternative is the collapse of her government.

And again that logic wasn't exactly on display on Tuesday, when the chief whip was heard talking to the Speaker about organising a possible emergency statement by the Prime Minister to be given on Wednesday morning, to prepare for a confidence vote - because he thought those Remainer rebels had done her in.

Or to put it another way, May on Tuesday had behavioural proof that the Remainers do not put the very highest priority on keeping her in 10 Downing Street.

All of which is to reinforce what John Major told me on Tuesday (in my interview with him for my "Now What" series, on ITV News's YouTube channel), that this is a government that could fall almost at any time, from the autumn through to next spring.


Boris Johnson has been critical of the PM's Chequers plan. Credit: PA

There are two alternatives to a general election.

One - for which Major said there was a strong case - is Greening's three-option referendum with ranked preferences (May's deal, no deal, staying in EU).

The other, which has belatedly become a serious talking point, would be the formation of a coalition government of national unity.

Arguably if parliament were to reject whatever deal May brings back from Brussels, and the revealed preference of MPs and Lords was for a more intimate relationship with the EU than she negotiates, then Parliament should choose a new executive, a new PM and ministers, to negotiate that relationship and see the UK through its implementation.

In a way, that would be the outcome most in keeping with the UK's parliamentary tradition.

But curiously, despite that tradition, it is very challenging to identify either the machinery for forming such a national government or the MPs to populate its highest positions.

To prove my point, ask yourself who in the current Parliament could be a Prime Minister able to enforce a common purpose among centrist MPs from Tories and Labour. Who would have the authority and gravitas? Who could command sufficient loyalty and respect? Who on earth could be a Brexit Churchill?

Here's the biggest flaw in the UK choosing to depart from the EU at this juncture: to do it effectively requires consensus; yet not for decades have people and their representatives been so polarised.