MPs have backed the Letwin Amendment, as parliament sits for the first Saturday in 37 years. 

This means the Prime Minister will have to try and get an extension for the UK leaving the EU. 

MPs were supposed to voting on Johnson's Brexit deal this afternoon. 

But the DUP said it would not back the deal as they say it is more harmful to the UK than the rejected deal former Prime Minister Theresa May drew up. 

Speaker John Bercow selected the Letwin Amendment.

The amendment withholds approval for Johnson’s Brexit deal until legislation implementing the UK's withdrawal from the EU is passed.

The vote on Johnson’s deal won’t happen today.

Instead he has to ask the EU for an extension. He has said he will not do this. He says the UK will leave the EU on October 31.

Letwin's amendment was passed 322 votes to 306.