MPs have forced a three-day deadline on Theresa May to come up with an alternative Brexit plan if her deal is rejected by the House of Commons.

In another bruising Commons defeat for the UK Government, a cross-party amendment demanding the deadline was backed by 308 votes to 297 on Wednesday.

Parliament's decision drastically reduces the time May has to plot her next move if she loses the pivotal meaningful vote next week, as is widely anticipated.

The Prime Minister previously had 21 days to state her intentions in the event the withdrawal agreement she struck with the EU was voted down by MPs.

The amendment, tabled by pro-Remain Conservative MP Dominic Grieve, follows Tuesday night's vote in favour of limiting UK ministers' powers to change taxes in the event of a no-deal Brexit.

SNP MP Philippa Whitford, who co-sponsored the Grieve amendment for the party alongside Joanna Cherry, said the Commons was "trying to avoid the Brexit cliff".

The vote saw angry scenes at Westminster as Tory MPs accused Speaker John Bercow of flouting Commons rules in allowing it to go ahead.

A series of MPs rose to complain that the original government motion should not have been amendable, with some suggesting the Speaker was not acting impartially.

Defending his decision, Bercow said: "My understanding is the motion is amendable, I'm clear in my mind about that."

He added: "I'm trying to do the right thing and make the right judgments.

"That is what I have tried to do and what I will go on doing."

One MP accused Bercow of having a "derogatory" sticker about Brexit in his car.

Conservative Adam Holloway said: "We've all noticed in recent months a sticker in your car making derogatory comments about Brexit.

"Have you driven that car with the sticker on?"

Bercow told MPs the car belonged to his wife, saying: "That sticker on the subject of Brexit happens to be affixed to or in the windscreen of my wife's car, and I'm sure he wouldn't suggest for one moment that a wife is somehow the property or chattel of her husband.

"She is entitled to her views, that sticker is not mine and that's the end of it."

His remarks drew cheers and applause from Labour and SNP MPs.

The debate on the Prime Minister's deal will resume later on Wednesday ahead of the meaningful vote on Tuesday, January 15.

It comes after the vote, originally planned for December, was cancelled by May so she could seek further assurances from Brussels on the contentious Irish border backstop.

She is now attempting to win over wavering MPs with fresh pledges on the issue.

The UK Government has published a new paper committing it to giving the Stormont Assembly a "strong role" in the triggering and operation of the backstop.