After the letter asking for a Brexit delay was sent to the EU, Jeremy Corbyn tweeted: "I told the Prime Minister to obey the law and despite his petulant posturing and bluster he finally has - he's asked for an extension.

"His damaging deal was defeated."

Shadow chancellor John McDonnell accused the Prime Minister of "behaving a bit like a spoilt brat" over Brexit.

Speaking on Sky News's Sophy Ridge on Sunday he said: "He may well be in contempt of Parliament or the courts themselves because he's clearly trying to undermine the first letter and not signing the letter.

"He's behaving a bit like a spoilt brat. Parliament made a decision, he should abide by it and this idea that you send another letter contradicting the first, I think it flies in the face of what both Parliament and the courts have decided."

McDonnell added: "We need the Bill before us, like we would consider any other Bill... we're saying bring it back next week and let's consider it.

"Do you know he might even meet the deadline of the 31st October if we go through a proper parliamentary process?"

Asked if Labour could back the Brexit deal, McDonnell said: "When the Bill comes forward, what we'll try to do, as in the normal way, put amendments to that Bill and see whether or not we can ensure that it meets the criteria that we've set out.

"The problem that we've got is this has become quite a fundamental choice about the future of our economy. Do we want to go down the Boris Johnson proposals of diverging from our major trading partner and deregulating our economy, undermining workers' rights, consumer and environment rights? No we don't.

"So what we'll try and do is, of course, try and amend that legislation and see if we can get agreement in Parliament."

Addressing Labour's lack of trust in Boris Johnson, McDonnell said: "This is a Conservative prime minister who has just betrayed his partners, the DUP.

"Of course we can't trust him.

"They were promised by Boris Johnson no border down the Irish Sea."

Asked what will happen to Labour MPs who vote with Johnson on Brexit, McDonnell said: "The whips will deal with them in the normal way.

"Thank goodness I'm not the Chief Whip."

Asked about Labour MPs, such as Melanie Onn and Caroline Flint who defied the whip and voted for the new Brexit deal on Saturday, McDonnell added: "There has to be a respectful whip on a number of these things where we take into account people's views.

"People have to be listened to.

"Melanie and Caroline have made detailed criticisms" of the deal that was put before Parliament.

He added: "That has to be listened to."

McDonnell said another Meaningful Vote on the deal on Monday would be "pointless" and a "political stunt" and advocated instead for the "real Parliamentary process of scrutinising that legislation".