Dozens of Conservative MPs are prepared to vote against the government in order to block the UK leaving the EU without a deal, one of the leaders of a group of more than 100 Tory politicians has said.

The warning to Theresa May was delivered on Friday by Andrew Percy of the Brexit delivery group – regarded in the party as a moderate band of remain and Brexit-supporting MPs – who said many wanted to act if the “intransigence” of hardline Brexiters led again to the prime minister’s own deal being rejected by parliament.

Percy, who voted to leave the EU, told BBC Radio 4’s Today programme “Some of my colleagues have got to recognise that the game they have thus far been playing with regards to this whole process is not going to end well for them and could potentially end with the delaying of – perhaps even no Brexit – which some of us have spent a lot of our parliamentary and political careers campaigning for.”

The threat, which was also contained in a letter from the leaders of the group to the party whip, leaves May facing the most serious cabinet revolt of her premiership next week as at least four cabinet ministers and almost a dozen junior ones are understood to be prepared to back a motion to delay Brexit.

Amid expectations that Tory MPs from the hardline European Research Group (ERG) would continue to oppose the prime minister’s package even if she returns from Brussels with changes to the backstop arrangements on the Irish border question, Percy said dozens of his colleagues were saying they would support such motions as the one proposed by the Tory MP Oliver Letwin and Labour’s Yvette Cooper, which is due to be debated on Wednesday.

A senior source close to those plotting the rebellion said there was no way the members of the government would resign voluntarily and May would have to sack them.

In what would effectively result in parliament taking control of the Brexit process, the amendment would require May to extend the article 50 deadline rather than allow the UK to leave the EU without a deal.

“A lot of colleagues have compromised from their positions,” Percy added.

“We are a group that has brought together leavers and remainers and I think people are seeing intransigence in other colleagues, people who are perhaps in denial about what the parliamentary arithmetic actually is on some of these matters and people are just growing increasingly frustrated that whilst we are prepared to make compromises other are not.”

While he accepted that the government could choose not to hold a meaningful vote next week, he said it was inevitable that this would happen at some point and that fellow Tory MPs would “naturally decamp”.

A letter sent by Percy and the other co-leader of the Brexit delivery group, Simon Hart, to the government chief whip, Julian Smith, said the reputation for competence of both the party and the government depended on their ability to delivery an orderly exit from the EU.

“Whilst we fully expect some changes to the backstop arrangements to be made by ministers in Brussels this week, there remains a chance that these will not satisfy some colleagues.”



