As Britain’s EU Withdrawal Bill makes its way back to the Lords and Commons, there’s a threat that Tory rebels could vote against the Brexit deal negotiated with the European Union. If they do this, they could “collapse the government”, warned leading rebel Dominic Grieve.

In an interview with the BBC on June 17, he suggested rebels would not back down in a current row with ministers about how much of a say MPs should get.

Last week the government avoided a defeat on the bill after agreeing to hold further talks with rebels.

Grieve, a former Attorney General, told BBC One’s Sunday Politics that he thought they had agreed MPs could have an “advisory” vote, that would not order the government to do anything, but would help people to “keep calm” during what would be a “critical situation”.

But after two days of talks, Grieve said a government amendment drawn up to avert a rebellion was changed at the last minute and was now “valueless”.

He implied rebels would vote against it this week: “I’m absolutely sure that the group is quite determined that the meaningful vote pledge, which was given to us, has got to be fulfilled.”

“The alternative is that we’ve all got to sign up to a slavery clause now, saying whatever the government does, when it comes to January, however potentially catastrophic it might be for my constituents and my country, I’m signing in blood now that I will follow over the edge of a cliff, and that I can tell you, I am not prepared to do,” he added.

According to the BBC, the government’s amendment to the EU Withdrawal Bill sets out what must happen in the event of three scenarios: If MPs vote down the UK-EU Brexit deal, if Theresa May announces before 21 January 2019 that no deal has been reached, or if 21st January passes with no deal being struck.

The main purpose of the EU Withdrawal Bill is to end the supremacy of EU law in the UK. It is also aimed at transferring existing EU law into UK law so the same rules and regulations apply on the day after Brexit.

But as it passes through parliament, MPs and peers have been trying to change it, in some cases adding bits on that would change the government’s Brexit strategy.