Both Labour and the Conservatives are braced for further walkouts as the creation of a new independent grouping of MPs continues to rip through the political landscape, with members of the Independent Group (TIG) saying they expected to see more MPs join them.

Heidi Allen, who yesterday announced she was leaving the Conservative party, along with fellow MPs Anna Soubry and Sarah Wollaston, said that around 100 of her former colleagues on the Tory benches shared her frustrations at the direction of the Conservative party.

Allen told ITV’s Peston: “I’d say a third of the party.”

‘My phone is melting’: Tory defectors buoyed by support Read more

It also emerged the former prime minister David Cameron made a last-ditch bid to try to stop the trio of Tories quitting.

High-profile ex-minister Anna Soubry said Cameron had reached out to the MPs as they prepared to turn their backs on the Tories for TIG.

Play Video 2:02 Tory defectors: why we're leaving the party – video

Soubry told the Times’ Red Box podcast that Cameron sent them a text saying: “Is it too late to persuade you to stay?”

As attacks on the prime minister from ex-Tory MPs intensified, Soubry accused Theresa May of having a personal “problem” with immigration.

Soubry told BBC2’s Newsnight: “The only reason why she will not agree to the single market is because of free movement of people.

“And I think what’s really worried me about Theresa, and she has history in the Home Office that supports this, because I’m an old barrister, I look at the evidence, and I think she’s got a problem with immigration. I really, honestly do.”

Asked if she meant it was a personal rather than policy issue for the PM, Soubry said: “Oh yeah, I think she has a thing about immigration and I don’t know where the hell that’s come from. Because in a modern Conservative party, when you again look at the evidence, you know, if we don’t have all these people that come and do all this work in our country, who on earth is going to do it?”

The Tory former attorney general Dominic Grieve said he would leave the party if the Government backed a no-deal Brexit.

Grieve told the BBC: “The government which I am supporting implementing a no-deal Brexit – what would I do? I would not be able to maintain my support of the government. I would have to leave the party.”

Lord Peter Mandelson said he felt “morally compromised” staying in Labour following antisemitic abuse endured by people such as ex-Labour MP Luciana Berger. But Mandelson urged Labour MPs to remain in the party.

Play Video 2:14 'We have all now resigned': seven Labour MPs quit party – video

The Labour peer told ITV’s Peston: “When I look at the sort of antisemitic abuse to which Luciana Berger has been subjected, but not alone, many others in the party, I feel ashamed, I feel actually quite morally compromised staying in a party that can spew out so much hatred towards other members of their own party.

“Now what is Jeremy Corbyn going to do about this? I mean, this risks growing from a splinter into a cavernous split in our party if he doesn’t take action to stop it.”