Theresa May is facing renewed pressure over her leadership amid growing disquiet over her handling of Brexit.
After Tory MPs met privately to discuss how to oust her, what does it take to topple the leader of the Conservative party?
- How would it begin?
To trigger a no-confidence vote in the party leader, 15% of Tory MPs must write to the chairman of the backbench 1922 Committee, currently Sir Graham Brady.
With 316 Conservative MPs in the House of Commons, Sir Graham must receive 48 letters to call a ballot.
- How many MPs have sent letters so far?
Not clear. Around 50 MPs discussed ways and means of getting rid of the Prime Minister at a gathering of the European Research Group on Tuesday, the Press Association understands.
A number of MPs told how they had already submitted letters of no confidence to Sir Graham and others discussed plans to follow suit.
- What if they do pass the mark?
Mrs May would need the support of more than 50% of Conservative MPs - currently 159 - in the confidence vote to stay in office.
- What would happen if she wins?
She can stay on as leader, however a narrow victory could seriously undermine her authority and may lead her to question whether it was right to carry on.
- What if she loses?
If the PM lost the vote she would not be able to stand in the subsequent leadership contest arranged by Sir Graham.
- What would the contest look like?
Candidates for the leadership must be nominated by two Conservative MPs. If only one candidate comes forward, he or she becomes leader.
If a number of would-be leaders are nominated, the list is whittled down to a shortlist of two by MPs.
The final two then go to a postal ballot of all party members, with the position of leader, and Prime Minister, going to the victor.
- How long would all that take?
Sir Graham would be responsible for overseeing the contest and setting a timetable for the campaign, which would be expected to last around 12 weeks.
Mrs May could remain in post during the campaign period.
- Have we not been here before?
The double resignations of David Davis and Boris Johnson as Brexit secretary and foreign secretary respectively over the so-called Chequers plans sparked fevered speculation a leadership contest could be triggered in July.
Such a challenge did not materialise and MPs disbanded for the summer recess.
They returned to Westminster last week.