Can Boris Johnson hold his party together if the EU moves on the backstop?

The prime minister was delighted by the polite reception he received from what he calls “our European friends” in Berlin, Paris and Biarritz. Despite a warning from Dominic Cummings, his top adviser, not to get carried away by positive talk from Angela Merkel, many Downing Street officials are convinced that there are signs the EU side is prepared to shift its ground.

Boris Johnson in his news conference at the end of the G7 summit said he was “marginally more optimistic” that a Brexit deal could be done that would avoid a no-deal exit on 31 October.

And a No 10 spokesperson told journalists yesterday: “What is clear is that if there is goodwill on both sides, and a determination to get things done, solutions to the backstop exist and the prime minister believes they should be discussed.”

She was pressed on whether a change to the backstop – the fall-back arrangements to keep the Irish border open – would be sufficient, and said: “We have been clear the changes we are seeking relate to the backstop.”

This could go down badly with several Eurosceptic Tory MPs, who have warned that simply dropping the backstop would not be enough. Iain Duncan Smith, David Davis, John Redwood, Steve Baker and Mark Francois have all said the backstop is not the only thing that makes the withdrawal agreement unacceptable. They complain about the divorce bill, the transition period and the persistence of EU law (because some citizenship issues have an eight-year phase-out).

On the other hand, Duncan Smith and Davis voted for Theresa May’s withdrawal agreement, along with Johnson, on the third time it was put to the Commons, in March. So I suspect they would in the end vote for a “better” agreement if Johnson asked them nicely.

We would then be back to the nail-biting numbers game that dominated parliament early this year. In the end 28 Eurosceptic Tory MPs voted against May’s deal, and she was 30 votes short of the total she needed to get the deal through. Johnson has appointed four of the 28, including Priti Patel, to government jobs, and may be able to persuade a handful more.

But Redwood, Baker and others are never going to vote for a deal, so the prime minister would be left needing about another 20 votes. If he can get changes to the backstop that are acceptable to the DUP, its 10 MPs would take him half way to the target.

Then he would still need 10 more votes from Labour MPs – such as Sarah Champion, who says she is prepared to leave the EU without a deal, and Stephen Kinnock, who now seems to regret not having voted for May’s deal.

Johnson said yesterday the chances of doing a deal were “touch and go”. Even if he succeeds, the same phrase describes his chances of getting it through parliament.