THERESA May is facing a no confidence vote by Tory MPs as her Brexit plan unravels amid cabinet resignations and calls for her to quit.

Jacob Rees-Mogg, the leader of the 60-strong European Research Group of Brexiter Tory MPs, said the Prime Minister had broken her promises to the country and had to go.

He has now written to the chair of the committee for backbench Tory MPs, the 1922 Committee, asking for a no confidence vote.

He said the country needed a leader who would “stand up to the European Union”.

He denied it was "a coup" or being motivated by personal ambition, and said he was not offering himself as leader.

He also revealed that he had been concerned for several weeks that Mrs May was losing the confidence of Tory MPs and that it would be "in the interest of the party and the country if she were to stand aside".  

He suggested Boris Johnson, David Davis, Esther Mcvey or Dominic Raab - all Brexiters who resigned from cabinet over Mrs May's plans - could replace Mrs May.

His letter is likely to prompt others to follow suit, making it all but inevitable that the threshold for a no confidence vote will be reached.

The trigger is 15% of Tory MPs - 48 in the current parliament - writing to the chairman of the backbench 1922 Committee, Graham Brady.

Mr Rees-Mogg said he was confident sufficient letters would go to the committee and trigger a vote that could end Mrs May's premiership.

The last time there was a no confidence vote in a Tory leader was in 2003 when Iain Duncan Smith lost the confidence of his colleagues.

That vote happened the day after sufficient letters reached the chair of the 1922.

If more than half of all Tory MPs - 158 - support the no confidence motion, it would trigger a Conservative party leadership contest.

Tory MPs would then pick two candidates who would go before the Tory party membership.

If Mrs May survived the no confidence vote, she could not be challenged again for a year.

However a narrow victory could still damage her authority irreparably.

Mr Rees-Mogg’s letter said the draft 585-page withdrawal agreement was “worse than anticipated and fails to meet the promises given to the nation by the prime minister, either on her own account or on behalf of us all in the Conservative party manifesto”.

He added: “That the Conservative and Unionist party is proposing a protocol which would create a different regulatory environment for an integral part of our country stands in contradistinction to our long-held principles.

“It is in opposition to the prime minister’s clear statements that this was something that no prime minister would ever do and raises questions in relation to Scotland that are open to exploitation by the Scottish National Party."