Parliament must not be able to “overturn the will of the British people”, Theresa May said as she faced a fresh battle over her Brexit legislation.

With the EU (Withdrawal) Bill returning to the House of Lords on Monday, peers looked ready to launch a fresh round of parliamentary “ping pong” and send amendments back to the Commons which Mrs May has said would tie her hands in negotiations with Brussels.

Tensions heightened after former attorney general Dominic Grieve warned that the Tory rebels he leads could “collapse” the Government if they disagree with the final outcome of withdrawal talks, and had the right to a proper say on Brexit.

Incident at Seven Sisters
Dominic Grieve said Tory rebels would only accept a ‘meaningful vote’ (Rick Findler/PA)

The Prime Minister said she had been listening to the concerns of critics but the legislation must not restrict her freedom in talks with Brussels.

“As we keep faith with people who voted to leave the European Union, and many of those who didn’t but are now saying ‘let’s just get on with it’, we need to make sure we are putting this legislation into place,” she said.

“But as we do that, of course we have been listening to concerns about the role of Parliament, but we need to make sure that Parliament can’t tie the Government’s hands in negotiation and can’t overturn the will of the British people.”

Mr Grieve insisted rebels would only accept a “meaningful vote” and not the “slavery clause” the Government was offering.

Nigel Evans says he does not want to 'fetter the PM during negotiations
Nigel Evans said he does not want to ‘fetter’ the PM during negotiations (PA)

But pro-Brexit MP Nigel Evans said he was “staggered” by Mr Grieve’s remarks.

He told BBC Radio 4’s The Westminster Hour: “I don’t want to fetter my Prime Minister while she’s negotiating the best deal for Britain.

“And part of that has got to be where, if (EU negotiator) Michel Barnier tries to give us a very bad deal, that she can turn around and say ‘no, I’d rather not do that’.”

Under Government plans, if MPs reject the agreement reached by Mrs May with Brussels, or if no deal has been obtained by January 21, Parliament will be offered the opportunity to vote on a “neutral motion” stating it has considered a minister’s statement on the issue.

Crucially, the motion will be unamendable, meaning MPs cannot insert a requirement for Mrs May to go back to the negotiating table, extend the Brexit transition or revoke the UK’s withdrawal under Article 50.

Expected Lords amendments to the Brexit legislation are set to return to the Commons on Wednesday.

Northern Ireland Secretary Karen Bradley urged fellow MPs to give the Government the freedom to secure the best deal.

“We cannot let Parliament tie the Government’s hands,” she said at an event in Omagh, Co Tyrone.

“We have to have the Government having the position to have the best negotiating position possible, so we can get the best deal for the United Kingdom.

“I would say to all of my colleagues: vote in a way to make sure the Government can get the best deal for the United Kingdom, because that’s what the people of the United Kingdom need and deserve.”