Speaking to Mrs May in the Commons, Mr Rees-Mogg said: “My Right Honourable friend, and she is unquestionably honourable, said that we would leave the customs union. Annex 2 says otherwise.

"My Right Honourable friend said that she would maintain the integrity of the United Kingdom. A whole protocol says otherwise.

"My Right Honourable friend said that we would be out of the jurisdiction of the European Court of Justice. Article 174 says otherwise.

“As what my Right Honourable friend says, and what my Right Honourable friend does, no longer match. Should I write to my Right Honourable friend, the member for Altrincham and Sale West?”

Several hours later, a European Research Group (ERG) spokesman confirmed Mr Rees-Mogg is to submit a letter of no confidence in the leadership of the Prime Minister. Addressing reporters outside of Parliament, Mr Rees-Mogg said: “What has been achieved today is not Brexit. What we need is a leader who will say to the European Union, it is impossible to divide up the United Kingdom.”

“It is impossible to agree to a situation where we have a perpetual customs union. It is impossible to pay £39 billion of taxpayers’ money for a few promises which was meant to be £39 billion for implementation of a deal. And it is impossible for us to allow the continuing jurisdiction of the European Court of Justice.”