Shadow Brexit secretary Sir Keir Starmer has forecast “very choppy times” next week as he predicted the Prime Minister will persist with her deal to leave the EU in the face of widespread Tory opposition.

He said the public could now see that the previous comments from Liam Fox that the negotiations would be the easiest in history, and David Davis’s belief that the full treaty would have been agreed by now, were “false promises”.

And Sir Keir said Theresa May had stopped trying to sell her Brexit deal as “good”, and was now merely arguing it was just better than leaving without one.

He was speaking at the Sage Gateshead ahead of an address to the North East Economic Forum.

Asked about the latest developments, Sir Keir said: “It’s very difficult to know what is going to happen next – yesterday in Parliament was an extraordinary day because for months we have been waiting for the Prime Minister to come back with her deal.

“She did so and what we saw were Cabinet resignations and Tory MP after Tory MP standing up and saying they would not support her.

“Obviously next week is all about whether the Prime Minister herself survives.

“If she does survive, I think she will persist with her deal and I don’t think it’s going to get through Parliament – so we’re in for some very, very choppy times next week.”

When asked whether this was the best possible deal she could have put forward, Sir Keir disagreed, saying: “I think the Prime Minister started in the wrong place and she has ended in the wrong place.

“I think we should have said from the outset we want a close economic relationship that really will protect manufacturing and really will protect our service sector and that means a long-term customs union and a single market deal for the UK.

“The Prime Minister says she is not prepared to negotiate that so she has come back with something that is, in my view, unacceptable.”

He added: “I have never accepted the argument that we must accept whatever Theresa May has cobbled together or face the prospect of No Deal.”

He believed Mrs May was effectively saying “I’ve got a deal, it’s not very good”, and he added: “She’s not even selling it as good now, she’s just saying ‘it’s better than leaving without one, I have brought back something pretty inadequate, if you don’t like that, you get even worse’.”

He said: “That is not a good enough choice and it’s not just Labour and the Opposition who is saying that, there are plenty of Conservative MPs who would not countenance us leaving without a deal and I think if it’s necessary, we will work together to stop No Deal happening.”

Asked how the EU will have viewed the last 48 hours of British politics, he replied: “I don’t think they can be very confident about what’s going on in the United Kingdom.

“They don’t want No Deal, that’s absolutely clear, I’ve been over to Brussels to the EU 27 on very many occasions in the last in the last two years and everybody wants a deal, but I think seeing what happened yesterday would’ve caused them huge concerns about where all this is heading.”