Leading Tory ministers, including pro-Brexit MPs such as David Davis and Boris Johnson, want Theresa May to loosen some of her “red lines” because they have “hamstrung” exit negotiations, a former senior government adviser has claimed.

James Chapman, who was Brexit Secretary Mr Davis's chief of staff until the snap election, said the Prime Minister's “absolutist” positions have made life very difficult for his former boss as he conducts talks with the European Union.

He suggested Ms May should loosen her commitment to leaving the jurisdiction of the European Court of Justice (ECJ) and hinted that Mr Davis and Mr Johnson could back a more liberal approach on immigration.

Mr Chapman's revelations came in an interview with Times deputy political editor Sam Coates for BBC Radio 4's The Week In Westminster.

The former adviser said of Mrs May: “Where she's taken some absolutist positions on particular issues, I'm thinking of the European Court of Justice.

“She's set a red line effectively for a conference speech that hamstrung these negotiations in my view.”

On Mr Davis, he went on: “There isn't anyone better to do this negotiation in Parliament in my view.

“He's a very tough, resilient operator. There have been red lines that have been set for him, that make the job he has to do very difficult.”

He pointed out that the two most high profile Brexiteers in the Cabinet, Mr Davis and Mr Johnson, were both liberal on immigration.

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The former political journalist said Ms May needed to realise that the political situation has changed she made the speech laying out her “red lines” at Lancaster House in London in January.

Ms May lost her majority at the snap general election held last month despite predictions that the Tory party could win a major landslide.

Mr Chapman said: “I think that there would be room to recalibrate some of this approach but at the moment she is showing no willingness to do this, I mean, she said that when she delivered the Lancaster House speech, that's the plan and that's what she is sticking to.

“Now this is a new Parliament, there's a new reality. She has to get these things through Parliament. There's an enormous amount of legislation. All sorts of moments where she's going to have to carry the Commons, let alone the House of Lords with her.

“So if she doesn't in my view show more flexibility, show more of the pragmatism that she did demonstrate in the Home Office, she won't get this stuff through Parliament.”