The chancellor has put himself at the head of the informal group of about 30 MPs discussing parliamentary manoeuvres to ensure the Commons has an opportunity to block a no-deal outcome in October.
It is understood that one option is to force a vote, before the summer recess, on whether to set aside a day in the autumn – before the Halloween deadline for Brexit – when MPs would control Commons proceedings in order to apply a last-minute brake if the new prime minister is taking Britain towards no deal.
One MP said that some ministers believe the process will lead to a Final Say referendum.
It is unclear how a vote could be engineered ahead of the 25 July start of the Commons’ summer break. If it proved possible, the autumn date for MPs to take control could be in place before the new prime minister takes office on 24 July.
News of the rebel group emerged as 70 members of the separate One Nation group of Tory MPs issued a warning to Mr Johnson and his leadership rival Jeremy Hunt not to use the suspension of parliamentary sittings – known as prorogation – as a means to secure a no-deal outcome.
And former prime minister Sir John Major revealed he will vote for Mr Hunt as Theresa May’s successor, on the grounds that he could not support someone who “misled the country” in the 2016 referendum.
Mr Hammond has made no secret of his concern that a no-deal withdrawal will be seriously damaging to the UK economy, and it is understood that he wants to ensure that MPs are not denied an opportunity to prevent it by parliamentary procedures or the suspension of the Commons.
He is understood to have held at least three meetings of the rebel Tories in his Commons office, with others thought to be sympathetic including cabinet ministers David Lidington and David Gauke, both of whom are thought likely to lose their government jobs along with the chancellor if Mr Johnson takes charge on 24 July.
One Tory MP told Sky News that successfully blocking no-deal Brexit in October would boost the chances of a second referendum.
“At this point there are only three options: pushing through a version of the withdrawal agreement with the help of the ERG [European Research Group of Tory Eurosceptics], which seems unlikely, a general election which would be catastrophic for the Tories or a second referendum which suddenly looks more appealing,” the MP said. “Some ministers explicitly see this ending in a second referendum.”
Former minister Phillip Lee, who quit the government to oppose Brexit, told The Independent that he was not part of the Hammond group but was not surprised to hear of fellow Tories preparing to fight to block a no-deal withdrawal in the autumn.
“Of course there are colleagues working together to try to stop ‘no deal’ without consent,” he said. “Anyone working on this is clearly working in the best interests of the country from our point of view.”
A cross-party bill to block a no-deal outcome was passed by a single vote in April, forcing Ms May to seek an extension to the Article 50 negotiation process.
Tory MP Guto Bebb, who rebelled on that occasion, said that the margin of victory could be expected to be wider in any future division, as Remain-leaning ministers in Ms May’s administration were likely to be out of government and freed from the constraints of collective responsibility.
“There are a number of people in office now who will not be there for much longer and will be able to follow their principles on this,” Mr Bebb told The Independent.
“The idea that there are insufficient numbers of Conservative MPs opposed to ‘no deal’ to stop it is somewhat unrealistic.”
Mr Johnson has put the promise to take Britain out of the EU with or without a deal by 31 October at the heart of his campaign for the Tory leadership, and has not ruled out the option of prorogation.
Mr Hammond told the BBC’s Political Thinking podcast it would be “shocking” if Ms May’s successor sought to “sideline” the House of Commons by avoiding a vote on no deal.
“The Commons has been clear already that it does not support a no-deal exit. That is my position, and as a backbencher I will continue to argue against a no-deal exit,” said Mr Hammond.
And Mr Gauke, the justice secretary, insisted that “a way will be found” to block a no-deal Brexit, saying: “I do think that parliament will find mechanisms to try to stop this from happening.”
Mr Lidington, who is Ms May’s effective deputy prime minister, has said he would not serve in any government that would intentionally leave without a deal in October, warning that it would be “very bad for the union both economically and politically”.
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