IAN Blackford has said Theresa May must not allow the UK to be held hostage by far-right Tories and the DUP.

Speaking in the House of Commons, the SNP Westminster leader stated that the SNP will be voting for revoking Article 50 or a People's Vote because "there is no such thing as a good Brexit”.

May has since told Tory MPs that she would quit if they back her Brexit deal.

READ MORE: Theresa May tells Tories she'll quit if they back her Brexit deal

Leading Brexiteers, including Boris Johnson and Jacob Rees-Mogg, have subsequently indicated that they would consider supporting her withdrawal agreement if it was brought back to the Commons.

Speaker John Bercow, however, has warned that he will not accept a third meaningful vote being brought forward this week without substantial changes.

During Prime Ministers Questions, Blackford said: "It is increasingly clear that the cost this Prime Minister will pay, to force her disastrous deal through, is the price of her departure.

"Yet again, another Tory Prime Minister is willing to ride off into the sunset and saddle us with a crisis in the UK – and an extreme-right Brexiteer in Downing Street.

"Does the Prime Minister feel no sense of responsibility for what she is about to do?

"The Prime Minister can still change course. It’s not too late.”

READ MORE: Labour MPs told to abstain from vote on Joanna Cherry's Brexit proposal

Referencing an anti-Brexit protest in London which attracted up to a million people and a petition signed by almost 6 million people calling for Article 50 to be revoked, the Ross, Skye and Lochaber MP urged the Prime Minister to reconsider her strategy.

"On Saturday, I joined opposition leaders, and a million people to demand a second EU referendum.

"Six million people have signed a petition online demanding the Prime Minister rethink her strategy.

"And today this House will give her a way out, a chance to prevent disaster.

"Will the Prime Minister finally respect the will of Parliament – or will she continue to allow Scotland and the rest of the UK to be held hostage by the extreme right of the Tory Party and the DUP?"