A Conservative grassroots revolt has been threatened next month if Theresa May does not set out specifics on when she will resign as Prime Minister.
MPs are currently powerless to remove Mrs May following a failed bid to boot her out as leader in December last year, led by Tory MP Jacob Rees-Mogg - but the National Conservative Convention are calling for a rule change.
Senior Tory activists will consider the question of Mrs May's leadership at an emergency meeting of association chairmen on June 15.
The treasurer of the 1922 Committee, Sir Geoffrey Clifton-Brown, told the Press Association he would back a bid to force Mrs May out with a no-confidence vote next month if she did not go of her own volition.
The Conservative MP for the Cotswolds said it was the Prime Minister's decision on when she should go, but he would "absolutely" support grassroots moves to try to topple her in June if her departure date was not imminent.
When asked what should happen if Mrs May failed to set out her own timetable for departure, he said: "It begins to get much more messy."
The move follows a meeting yesterday between the Prime Minister and chairman of the 1922 committee Sir Graham Brady, with the outcome of the talks set to be revealed today.
Sir Graham has faced angry calls from backbenchers for "clarity" on Mrs May's timetable for standing down and triggering a leadership contest.