John Bercow has announced he will stand down as Commons Speaker at the end of next month unless an election is called before then.
In an impassioned speech to the Commons, Mr Bercow - who has been Speaker for 10 years - also said he would step down as an MP.
Formerly a Tory MP, the party was said to be planning to break from convention and stand a candidate against him at any looming general election.
Bercow and the Brexiteers in the Conservative party have repeatedly clashed over parliament's role in shaping the Brexit process.
As he announced the news live in the chamber, Labour and the opposition benches granted him a rapturous standing ovation as many on the government stayed seated.
Addressing the Commons while his wife looked on from the gallery, Mr Bercow said: "At the 2017 election, I promised my wife and children that it would be my last.
"This is a pledge that I intend to keep. If the House votes tonight for an early general election, my tenure as Speaker and MP will end when this Parliament ends.
"If the House does not so vote, I have concluded that the least disruptive and most democratic course of action would be for me to stand down at the close of business on Thursday October 31."
He continued: "Least disruptive because that date will fall shortly after the votes on the Queen's Speech expected on October 21 and 22.
"The week or so after that may be quite lively and it would be best to have an experienced figure in the chair for that short period.
"Most democratic because it will mean that a ballot is held when all members have some knowledge of the candidates.
"This is far preferable to a contest at the beginning of a parliament when new MPs will not be similarly informed and may find themselves vulnerable to undue institutional influence."
The Speaker added he has "sought to be the backbenchers' backstop", and thanked his team in the Speaker's House for their work behind the scenes.
Mr Bercow said: "I could not serve this House without a small but superb team in the Speaker's House, my wife Sally and my three children Oliver, Freddie and Jemima."
He added: "From the bottom of my heart, I thank them all profusely."
His wife Sally Bercow could be seen smiling on from the gallery.