I am reliably told that Theresa May told Boris Johnson, Iain Duncan Smith, Steve Baker, Jacob Rees-Mogg, David Davis et al at Chequers that she will quit if they vote for her deal, including the backstop they hate.
But she gave no specifics. So there is not a lot of trust she would actually quit.
And the problem is that even if she persuades all Tory ERG MPs to vote for her unamended Withdrawal Agreement, which she won’t (because although Mogg and his supporters may succumb to her call for loyalty, Baker and the Brexiter purists will resist her blandishments) and she also successfully woos Northern Ireland’s 10 DUP, she still does not have the numbers.
May has alienated too many Labour MPs and Tory Remainer ultras (Grieve, Greening, Gyamah inter alia) to win the vote. So even with May offering herself for ritual sacrifice on the Brexiter altar, the ERG Brexiters and DUP may well say thank you very much, and vote against her anyway.
Why should they compromise their principles, and alienate their loyal supporters, for May’s doomed project?
Robert Peston is ITV's Political Editor. This article originally appeared on his ITV news blog.