Grassroots Tories believe they are just weeks away from triggering a little-known process that could help to bring down Theresa May.

Party chairmen are circulating a petition calling for the party's National Convention, which represents the grassroots, to call an Extraordinary General Meeting to pass a vote of no confidence in Mrs May, the Tory leader.

If the petition motion is signed by more than 65 association chairmen, the party is obliged to hold the meeting. So far between 40 and 50 party chairmen have signed it, and the threshold could be passed as early as next week.

Dinah Glover, the London East area chairman who has organised the petition, said the extraordinary meeting – the first one in the party’s history - could be held as soon as next month.

Ms Glover told The Telegraph: “There is a lot of frustration and anger within the party – this is a route that we have to demonstrate those feelings so we can encourage MPs to make those feelings known.”

The meeting would allow MPs “to make their feelings known as well so they understand the level of anger, not only in the voluntary party but across the elected members as well," she said.