Theresa May is facing a fresh Brexit showdown as MPs vote on Parliament’s role in Britain’s exit from the European Union.

Flagship legislation returns to the Commons after the Lords again backed giving MPs a “meaningful” say on the final deal.

The Prime Minister staved off a Tory rebellion on the move last week but faces a bruising battle in the latest round of voting.

Brexit
Dominic Grieve has led efforts to win a meaningful vote (Stefan Rousseau/PA)

Dominic Grieve, one of the leading figures in the stand-off, said he expected negotiations to “go right to the wire”.

The possibility of a rebellion “all depends on where we go on the negotiations and at the moment I don’t know the answer”, the former attorney general added.

But Brexiteers are said to be increasingly confident of victory.

Tory Remainer Anna Soubry posted a lengthy statement about why she will rebel and denied being a “traitor”.

“Getting Brexit right is vital and is the most  important set of decisions our country has taken in decades,” she wrote.

“Whatever we were told during the Referendum, you can’t simply unravel 43 years of membership of the EU in a year or two and getting a new trading deal is far from the ‘simplest’ of matters as we were assured.”

Peers backed an amendment to the EU (Withdrawal) Bill, tabled by Viscount Hailsham, on Monday that would require the Government to allow MPs to vote on how it would proceed in the absence of a Brexit deal by January 21 next year.

MPs will now vote on whether to adopt the motion, which was brought in after pro-EU rebels led by Mr Grieve accused the Government of reneging on measures they believed had been agreed to see off a rebellion last week.

Prime Minister Theresa May has warned against any moves to “tie her hands” during negotiations with Brussels, saying that Parliament must not be able to “overturn the will of the British people”.

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.

The Commons vote comes as Guy Verhofstadt, the European Parliament’s Brexit co-ordinator, appears before MPs at hearings of the Exiting the EU and Home Affairs select committees.