MPs mount bid to close 'no-deal' Brexit loophole ahead of crunch vote

Ex-Tory puts forward 'insurance policy' to PM's plan ahead of historic Saturday sitting

Backbench MPs will seek to close a no-deal loophole by forcing Boris Johnson to delay Brexit until the legislation has been passed.

Expelled Tory MP Sir Oliver Letwin has put forward an "insurance policy" amendment to withhold MPs' approval for the Brexit deal until all the legislation has passed through parliament.

Ahead of the critical Saturday sitting, it emerged that the cross-party amendment could scupper the prime minister's plans by preventing a clean vote on the Brexit deal.

The move indicates the distrust between Downing Street and MPs opposed to no deal, who want the Brexit deal written into law before 31 October deadline to prevent a disorderly exit from the EU.

It comes as Mr Johnson embarked on a last-ditch charm offensive to sell his deal to MPs, with focus on three key groups - Labour leavers, Tory Brexiteers and sacked Conservative rebels.

The prime minister faces an uphill battle to secure the magic 320 votes to get the deal over the line, after his DUP allies said they would not support the agreement.

Sir Oliver said his amendment, which been signed by several senior ex-Tories, including Philip Hammond, the former chancellor, was vital to ensure there was "no slip up".

He told the Today programme: "What I want to make sure is that if the House of Commons on Saturday - as I hope it will - approves the principle of the deal, it doesn't let the government off the hook of the Benn Act.

"We get the extension in place so that there is no slip up and we don't find at a later stage, next week some time or the week after, that when the implementing legislation is going through, somehow that doesn't get through.

"Because that of course, if we didn't have an extension in place, would lead not to the deal I hope we will get, but rather to dropping out without a deal on 31 October. I want to prevent that happening."

The row centres on a loophole in the Benn Act, a backbench law tabled by Labour's Hillary Benn, which aims to prevent a no-deal Brexit on 31 October.

Under the terms of the Act, Mr Johnson must ask the EU for a further delay to Brexit if a deal is not approved by Saturday, 19 October.

But there is no legal obligation on the government to actually implement the terms of the deal, even if MPs have approved it.

Stephen Hammond, another former Conservative, said the move would act as a safeguard, in case Downing Street attempts to evade the law to avoid a no-deal Brexit.

He said: "What it is born out of is the concern that someone might choose to vote for tomorrow's deal, thereby satisfying the Benn Act, and then choose to do something either by accident or by design which frustrates the implementation bill and then there is a possibility of us leaving the European Union without a deal."

SNP Westminster leader Ian Blackford also tabled a separate amendment calling for an extension until at least January, to allow time for an early general election.

Angus MacNeil, another SNP MP, has also put forward a bid to demand the government revokes article 50.

The prime minister's official spokesman said: "I'm not going to get into amendments that have not been accepted."

John Bercow, the Commons speaker, will decide which amendments to accept at the start of the debate. It is understood that MPs can submit amendments for consideration up until the debate begins.