Thirty Tory MPs led by Chancellor Philip Hammond are plotting to stop a no-deal Brexit in October in a move which would raise the chance of a second referendum, Sky News understands.
The informal group of rebels, mostly serving ministers, have held three meetings since Theresa May announced her departure a month ago, about how to prevent the UK crashing out on 31 October.
Two sources said the group’s key aim is to secure – within the next three weeks before parliament rises for the summer – a date in October on which MPs will control the agenda and can force through legislation.
Along with other Tories who are currently on the backbenches, it is expected that the overall bloc of MPs opposing no deal will range from 25 to 45 depending on the methods used.
If they are successful and Britain is still in the EU on 1 November without a new, more acceptable deal from the EU, the move is likely to boost the chances of a second referendum.
One Tory MP said: “At this point there are only three options – pushing through a version of the Withdrawal Agreement with the help of the ERG, which seems unlikely, a general election which would be catastrophic for the Tories or a second referendum which suddenly looks more appealing. Some ministers explicitly see this ending in a second referendum.”
The meetings are understood to have been held in the Chancellor’s Commons office, with Mr Hammond increasingly vocal about the risks to the economy and UK union.
Cabinet ministers David Lidington and David Gauke, who are widely expected to lose their jobs in the next government over their opposition to a no-deal Brexit, are active in the group.
The last time MPs took control of the agenda was in early April, when Yvette Cooper and Oliver Letwin led a successful attempt to force the prime minister to extend the Brexit deadline from mid-April to June.
One MP told Sky News: “There will be another Cooper Letwin-style attempt to try and stop no-deal.
“We don’t know what the vehicle is yet but the first aim is to get a date. It will be in October, when minds are focused on leaving without a deal.”
This could involve amending no deal legislation or regulations or other “vital” laws which will be needed by the new administration.
Another Conservative familiar with the discussions said the group would be making its presence felt in the same way as the hard Brexiteer “Spartans” who refused to vote for the prime minister’s deal, saying: “They are looking at the way the ERG played hardball.”
However another Tory MP on the backbenches cautioned not to overestimate the bravery of those who are currently ministers but will lose their job when the new PM comes into office.
“I just wonder if they realise how hard it is to stand firm. They’ve all been very protected as ministers,” said the sceptical MP.
It has been suggested the future prime minister could even be helped by the threat of parliament blocking a no-deal Brexit, as a way to convince hard Brexiteer MPs into voting for a revamped version of the withdrawal deal.
Justice Secretary David Gauke has said he has no doubt “a way will be found” to prevent the UK leaving without an agreement in place, but ruled out voting no-confidence in the government.
However, speaking at a Hustings event in Darlington on Friday, Mr Johnson said no-deal planning needed to be stepped back up after preparations “slid off” following the previous 29 March deadline.
The Chancellor has used his final weeks in the job to rail against the economic damage which would be wreaked by a no-deal.
He told MPs at Treasury questions this week it “will be bad for the UK, bad for the British economy, bad for the British people”, even suggesting he might vote with Labour to prevent it.
Mr Hammond has also attacked the spending plans of both Mr Johnson and Mr Hunt, saying there would be no “headroom” left for giveaways if there is a no-deal on 31 October.
MPs hoping to stop a no-deal suffered a blow earlier this week as an expected showdown in parliament was blocked by the Speaker John Bercow.
Rebel Tory Dominic Grieve and Labour’s Margaret Beckett tried to secure a controversial amendment to cut off funding to government departments if there is a no-deal Brexit, but the speaker refused to grant it.
An aide to the Chancellor said: “He regularly speaks to colleagues on all sides of the argument.”