A cross-party group of MPs look set to back a new amendment that would force the UK Prime Minister to seek a Brexit extension if the new deal is passed.

The amendment, put forward by MP Oliver Letwin is aimed at blocking an accidental no-deal Brexit.

It comes amid concern pro-Brexit MPs could approve the new deal – but delay the legislation required to bring it into force, thus leading the UK into a no-deal scenario by default once the October 31st deadline passes.

The Letwin amendment would trigger a law requiring UK Prime Minister Boris Johnson to request an extension, with MPs then free to debate the new laws with the deadline removed.

File photo of Conservative MP Oliver Letwin, 04-04-2019. Image: Xinhua/Zheng Huansong

Mr Letwin said he wants to make sure there is no accidental crash-out.

"My aim is to ensure that Boris' deal succeeds, but that we have an insurance policy which prevents the UK from crashing out on October 31st by mistake if something goes wrong during the passage of the implementing legislation," he said.

He said the amendment "does not have any effect on the actual important vote – which is if we support this deal or don't."

"I do support this deal," he said. "I will vote in favour of this deal tomorrow because I think it is a very sensible deal.

"The amendment is to make sure that we have an insurance policy that means if for some reason something goes wrong when the legislation goes through, we would have already secured the extension […] so we won't crash out of the EU by mistake."

He said the UK could still leave the EU on October 31st – provided the required legislation is passed.

However, there are fears the move could open the door for a host of other amendments – which could see the UKs exit pushed further and further down the road.

Meanwhile, talks are continuing this evening at Downing Street as Mr Johnson attempts to convince MPs to back the deal.

The UK Labour Party, the Liberal Democrats, the DUP and the SNP have all said they will not back the deal.

However, a handful of Tory and Labour MPs who refused to back the agreement brought home by his predecessor have already said they will support the new deal.

It will be debated at a special sitting of the House of the Commons tomorrow.

With reporting from IRN ...