Theresa May must deliver the Brexit she promised or risk collapsing the Government, a leading Brexiteer has warned ahead of crucial Cabinet talks on the UK’s exit strategy.

Jacob Rees-Mogg said the Prime Minister and her top team must decide at a meeting at Chequers on Friday if they would stand by her pledges or reduce “a once-proud country” to a “tremulous state that sees Brexit as mere damage limitation”.

It comes as Mrs May faces repeated warnings that senior figures in her government are on manoeuvres in preparation for a leadership battle.

Writing in The Daily Telegraph, Mr Rees-Mogg warned the PM she was in danger of splitting the party like Sir Robert Peel, who plunged it into the political wilderness for nearly three decades following bitter divisions over trade reforms.

The chairman of the European Research Group of Brexit-backing Tories said: “Theresa May must stand firm for what she herself has promised.

“One former Tory leader, Sir Robert Peel, decided to break his manifesto pledge and passed legislation with the majority of his party voting the other way.

“This left the Conservatives out of office for 28 years.

“At least he did so for a policy that works. At Chequers [Mrs May] must stick to her righteous cause and deliver what she has said she would, she must use her undoubted grace to persevere.”

It comes as the PM’s chief Brexit official reportedly told ministers they have no chance of striking a bespoke trade deal with Brussels.

Briefing Cabinet ministers ahead of the Chequers talks, Oliver Robbins is said to have painted a bleak picture of the situation, with a source telling The Times they came out of the meeting thinking “we were even more screwed than we were before”.

Business Secretary Greg Clark and Commons leader Andrea Leadsom both refused to rule out an extension to transition arrangements in the face of demands from Tory backbenchers for the timetable to be maintained.

Mr Clark said the decision must be “guided by the facts and the evidence” and Mrs Leadsom said December 2020 was not a “magical date”.

Mrs May will bring together her Cabinet at her country residence to thrash out details of a white paper setting out the UK’s plans for areas such as trade.

Brexiteers oppose the PM’s favoured option of a customs partnership with the EU, which would see the UK collect tariffs set by the EU customs union on goods entering the country on behalf of the bloc.

Their “max fac” alternative would, rather than scrapping customs checks, uses technology to minimise the need for them.

Both options have been dismissed by the EU.

James Brokenshire said there was “no doubt that there is strong views on either side” over Brexit in Cabinet but insisted he was “confident” Mrs May’s top team could reach an agreement at the meeting.

The Communities Secretary said the Government was planning for “all eventualities”.

Labour’s economy secretary in Wales will meet Airbus, which has warned it could pull out of the UK over Brexit, and other exporters for talks on Monday.

Ken Skates said he wanted to meet prominent exporters to “listen to their views on the opportunities and threats posed by Brexit”.

The Prime Minister will update MPs on Monday following a meeting with fellow EU leaders in Brussels last Friday.