Oliver Letwin said there were “various” ways to successfully bind the hands of the prime minister – but he was “not terribly optimistic” that MPs would settle on which route to pursue.
“I don’t see yet emerging an agreement on that,” Sir Oliver said – acknowledging there were “different first preferences” among the MPs, of many different parties.
The comment lifted the lid on intense behind-the-scenes rows, after a week in which party leaders also clashed publicly on who should be a caretaker prime minister, if Mr Johnson is toppled.
Instead, the Tory moderniser – a supporter of Theresa May’s failed deal – stressed the need for MPs to reach a consensus on “what the end game is”.
“You can’ just say I don’t want to have a no deal exit – you also have to say ‘what do I want to have’ and get agreement on that,” Sir Oliver told BBC Radio 4.
He added: “At the moment, I’m not terribly optimistic about all this, because I don’t see yet emerging an agreement on that
“That’s why I think we need to talk, talk a lot, talk frankly. We have to try to find something that a majority will agree to.”
The MPs are believed to be divided on when and how to pass legislation to prevent a crash-out Brexit on Halloween and on the extent of the changes to the law.
However, many anti-Brexit MPs believe the fresh bid must go further to thwart Mr Johnson, who could simply refuse to co-operate with EU leaders – keeping a Halloween no-deal as the legal default.
Some are arguing for changing that default to require Article 50 to be revoked altogether if no extension has been granted by the eve of Halloween, keeping the UK in the EU.