Dominic Grieve says Tory rebels are prepared to “collapse the government” if that is necessary to block the “catastrophic” damage from a botched Brexit.

The group’s leader vowed they would not back down in a further Commons showdown this week to secure a “meaningful vote” designed to block a “no-deal” exit.

Instead, Mr Grieve accused pro-Brexit hardliners in his own party of seeming to “prefer chaos”, rather than reach an agreement to give MPs a voice in the process.

Asked if he was ready to defeat the government, he replied: “The group is quite determined that the meaningful vote pledge that was given to us has got to be fulfilled – I think that is abundantly clear.”

And, asked what might happen if Theresa May’s deal was later rejected, Mr Grieve said: “We could collapse the government. And I can assure you, I wake up at 2am in a cold sweat thinking about the problems that we have put on our shoulders.”

But the former attorney general vowed not to bow to pressure and risk leaving the EU without an agreement – which he called a demand to “sign up to a slavery clause”.

It asked that “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 the cliff”, he warned.

“That I can tell you I am not prepared to do,” Mr Grieve told the BBC’s Daily Politics programme.

The biggest issues facing UK on leaving EU Show all 8 1 /8 The biggest issues facing UK on leaving EU The biggest issues facing UK on leaving EU Post-Brexit immigration workers sorting radishes on a production line at a farm in Norfolk. One possible post-Brexit immigration scheme could struggle to channel workers towards less attractive roles - while another may heighten the risk of labour exploitation, a new report warns. PA The biggest issues facing UK on leaving EU Customs union A key point in the negotiations remains Britain's access to, or withdrawal from, the EU customs union. Since the referendum there has been hot debate over the meaning of Brexit: would it entail a full withdrawal from the existing agreement, known as hard Brexit, or the soft version in which we would remain part of a common customs area for most goods, as Turkey does? No 10 has so far insisted that “Brexit means Brexit” and that Britain will be leaving the customs union, but may be inclined to change its position once the potential risks to the UK’s economic outlook become clearer. Alamy The biggest issues facing UK on leaving EU Northern Ireland-Irish border Though progress was made last year, there has still been no solid agreement on whether there should be a hard border between Northern Ireland and the Republic of Ireland. To ensure borderless travel on the island, the countries must be in regulatory alignment and therefore adhere to the same rules as the customs union. In December, the Conservative Party’s coalition partners, the DUP, refused a draft agreement that would place the UK/EU border in the Irish Sea due to its potential to undermine the union. May has promised that would not be the case and has suggested that a “specific solution” would need to be found. Getty The biggest issues facing UK on leaving EU Transition period Despite protests from a small number of Conservative MPs, the Government and the EU are largely in agreement that a transitional period is needed after Brexit. The talks, however, have reached an impasse. Though May has agreed that the UK will continue to contribute to the EU budget until 2021, the PM wants to be able to select which laws made during this time the UK will have to adhere to. Chief negotiator Michel Barnier has said the UK must adopt all of the laws passed during the transition, without any input from British ministers or MEPs. EPA The biggest issues facing UK on leaving EU Rights of EU citizens living the UK The Prime Minister has promised EU citizens already living in the UK the right to live and work here after Brexit, but the rights of those who arrive after Brexit day remains unclear. May insists that those who arrive during the transition period should not be allowed to stay, whereas the EU believe the cut-off point should be later. Getty The biggest issues facing UK on leaving EU Future trade agreement (with the EU) Despite this being a key issue in negotiations, the Government has yet to lay out exactly what it wants from a trade deal with the EU. Infighting within the Cabinet has prevented a solid position from being reached, with some MPs content that "no deal is better than a bad deal" while others rally behind single market access. The EU has already confirmed that access to the single market would be impossible without the UK remaining in the customs union. Getty The biggest issues facing UK on leaving EU Future trade agreements (internationally) The Government has already begun trying to woo foreign leaders into prospective trade agreements, with various high profile state visits to China, India and Canada for May, and the now infamous invitation to US President Donald Trump to visit London. However the UK cannot make trade agreements with another country while it is still a member of the EU, and the potential loss of trade with the world's major powers is a source of anxiety for the PM. The EU has said the UK cannot secure trade deals during the transition period. EPA The biggest issues facing UK on leaving EU Financial services Banks in the UK will be hit hard regardless of the Brexit outcome. The EU has refused to give British banks passporting rights to trade within the EU, dashing hopes of a special City deal. However according to new reports Germany has suggested allowing trade on the condition that the UK continues paying into the EU budget even after the transition period. Getty

The comments set up another dramatic showdown on Wednesday, when the EU Withdrawal Bill returns to the Commons – with the Lords certain to reject an attempted government compromise on Monday.

A rebellion was aborted last week when the prime minister partially agreed to the rebels’ demands for MPs to have a decisive vote to block a no-deal Brexit.

They were stunned when the amendment was later altered, so that MPs would only be able to debate a no-deal outcome, rather than change the government’s course.

The Independent understands the last-minute change was made after fierce objections from Brexiteers and the intervention of David Davis, the Brexit secretary.

Earlier, Ms May denied she had gone back on a promise given to the pro-EU Tory MPs, insisting she was a woman of her word.

“I did indeed meet a group of my fellow MPs. I listened to their concerns and I undertook to consider their concerns,” she told The Andrew Marr Show.

But she suggested she would not back down, vowing: “Parliament cannot tie the hands of government in negotiations.”

The rebels believe they have the numbers to win, but Brexiteers are equally convinced they are exaggerating their strength – pointing to a nailbiting vote on Wednesday.

The prime minister also revealed her long-promised white paper on long-term Brexit aims would finally be published in the week beginning 9 July.

It was due to set out the UK’s negotiating position ahead of the crucial EU summit at the end of June, but was delayed by cabinet infighting over customs and the Irish border.

Ms May again insisted she could not agree to any EU move to create a trade border between Britain and Northern Ireland, stating: “That’s not right. That’s not acceptable.”