Theresa May is set to climbdown on her promise to stamp the Brexit date into UK law on Wednesday after shying away from another confrontation with Tory rebels.

Ms May had been warned she faced a second bruising defeat if she tried to rigidly enshrine the March 2019 Brexit day on the face of her EU Withdrawal Bill.

Instead, on Wednesday evening she is expected to agree to a compromise proposal which allows for a degree of flexibility in when Brexit happens.

It comes as Theresa May is set to face a major two-hour grilling in Parliament at the hands of the influential Liaison Committee, made up of the chairs of all the other Commons select committees. 

The compromise amendment to Ms May’s Eu Withdrawal Bill is being brought forward by Sir Oliver Letwin, who said: “All the indications I’m getting are that the Government is likely to accept it.”

It was last month that the Prime Minister announced a change to the her Brexit Bill that would set the date of withdrawal at 11pm on 29 March 2019.

The plan angered Tory rebels who want the Brexit deal she agrees with Brussels enshrined in a full Act of Parliament, as they feared there may not be enough time to pass it before the March date came and went.

Enough rebels, many of who had already defeated the Government in a previous vote on the Bill, pledged also to oppose her plan on the Brexit date.

With Ms May’s authority already dented and concern that a second defeat would do further damage, Sir Oliver tabled his new amendment as a compromise.

If accepted on Wednesday evening, it will leave the date on the face of the Bill but allow Parliament a vote to change it if negotiations overrun.

The new amendment has the support of dozens of Tory MPs, including Brexit supporters Jacob Rees-Mogg and Sir William Cash and Remain supporters George Freeman and Nick Boles.

As the process continues, Transport Secretary Chris Grayling insisted the Government is not in danger of falling and would see out a full term in office.

“We have got a strong relationship with the DUP. We have got a team of Conservative MPs who are committed to taking this country forward,” he told BBC Two’s Newsnight.

But Mr Freeman, former chairman of the Prime Minister’s policy board, warned that getting Brexit wrong could be a “catastrophe” for conservatism.

He told the BBC: “It is really urgent, that as the Prime Minister sees through the noble and, frankly, thankless task of negotiating Brexit that under her leadership a messianic piece of work has begun, to make this a moment of Conservative renewal that can inspire those who didn’t vote for it.

“I think it’s very urgent. I think if we don’t, this is in danger of being a Brexit that breaks, not makes conservatism. We are in a risk of this being a moment, a catastrophic moment, where conservatism isn’t forgiven by a generation that didn’t vote for it.”