Two more senior moderate Conservative MPs are facing deselection votes at their annual meetings as the “purple momentum” assault on them by hardline Eurosceptics gathers pace.

Sir Alan Duncan is facing a motion of no confidence at his annual meeting, while Sarah Wollaston, chairman of the Health select committee, is facing a challenge at either an extraordinary meeting in the next fortnight or an AGM.

The news came as Steve Barclay, the Brexit secretary, is due in Brussels on Monday for talks with EU chief negotiator Michel Barnier, ahead of a key speech on Mrs May’s Brexit deal by Geoffrey Cox, the Attorney General, on Tuesday.

Theresa May, the Prime Minister, is also set to go to Brussels this week for more talks about agreeing a Withdrawal deal to take the UK out of the EU at the end of next month.

Sir Alan, a senior foreign office minister who has been critical of Eurosceptic Tories, has already been readopted by his local party’s executive but is now facing a motion of no confidence at the party's annual meeting on March 15.

In Dr Wollaston’s constituency, a letter signed by more than 50 members calling for an extraordinary meeting to deselect the MP will be presented to John Smith, the local party chairman on Monday. If that fails a motion is set to be tabled at the party's annual meeting on March 30.