JOHN Bercow has announced he is to step down as the House of Commons Speaker on October 31 unless there is a general election beforehand.

In a move that will continue the controversy about his tenure right to the very end, the likely date of his departure means he will be in the chair during what promises to be a particularly turbulent period at Westminster in the run-up to the date when Britain could well see its second Brexit Day pass without the country having left the EU following the granting of another extension by the EU.

In practical terms, it could also mean Mr Bercow, an avowed Remainer, would be in place to facilitate any action the so-called “Rebel Alliance” might try to use to stop Boris Johnson getting round the will of Parliament to delay Brexit further.

In recent times, the Speaker has faced fierce criticism from Brexiteers, who have questioned his impartiality on the issue of Britain’s membership of the EU.

Watched by his wife Sally from the public gallery, Mr Bercow, in the chair for 10 years since taking over from Glasgow MP Michael Martin in 2009, also announced he would step down as an MP; he was first elected as Conservative MP for Buckingham in 1997. Before he became Speaker, the 56-year-old served in the Shadow Cabinets of Iain Duncan Smith and Michael Howard, where he held the respective portfolios of Shadow Chief Secretary to the Treasury and Shadow International Development Secretary.

His announcement comes just 48 hours after Tory high command made clear it would break a long-held convention and stand a candidate against the sitting Speaker in his Buckinghamshire seat at the next election. Mr Bercow broke his news with the Conservative side of the chamber largely empty while the Opposition benches were full.

He told MPs: “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."

The Speaker said his time in the chair had been the greatest privilege and honour of his professional life and that he "sought to be the backbenchers' backstop," thanking his team in the Speaker's House for their work behind the scenes.

"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." Mrs Bercow could be seen smiling on from the gallery.

Her husband told MPs that he could not have served Parliament without their support and, throughout his time in the chair, he had sought to increase the “relative authority of this legislature for which I will make absolutely no apology".

He added: "This is a wonderful place filled overwhelmingly by people who are motivated by their notion of the national interest, by their perception of the public good and by their duty, not as delegates, but as representatives, to do what they believe is right for our country."

In a final note of warning to the Government, he said: "We degrade this Parliament at our peril."

Mr Bercow's time in the chair has seen a deal of controversy outwith Brexit.

Last year, the Speaker faced claims of bullying from his former private secretary Angus Sinclair, which he strenuously denied. He established an independent body to examine claims of harassment and bullying at Parliament after facing calls to quit following allegations such practices had gone on for years.

After his announcement, tributes poured in led by Jeremy Corbyn, who hailed Mr Bercow as a "superb" Speaker.

“In your role as Speaker you have totally changed the way in which the job has been done. You've reached out to people across the whole country,” declared the Labour leader.

"This Parliament is stronger for your being Speaker. Our democracy is the stronger for your being the Speaker. And whatever you do when you finally step down from Parliament, you do so with the thanks of a very large number of people."

He quipped: “Your choice of timing and dates is incomparable and will be recorded in the history books of parliamentary democracy."

For the Government, Michael Gove said it was clear Mr Bercow loved the Commons and democracy, declaring: "Your commitment to your principles and to your constituents is unwavering and an example to others."

The Cabinet Office Minister joked he hoped the Speaker would not take it personally when he voted later today for an early general election, noting: "It is the case that however controversial the role of the backstop may be in other areas, your role as the backbenchers' backstop has certainly been one that's been appreciated by individuals across this House."

He added: "Your love of democracy is transparent in everything that you say and do. I want to, on behalf of myself as an individual and on the behalf of the Conservative Party, to say thank you."

Ian Blackford for the SNP said: "We are grateful that you will be with us until the end of October. You have been a great friend to many of us in the House."

Jo Swinson, the Liberal Democrat leader, said casting her vote to elect Mr Bercow as Speaker was the most important vote she had taken as an MP and thanked him for introducing reforms allowing for Parliament to be more accessible for parents.

Ladbrokes placed Lindsay Hoyle, the Deputy Speaker, at 4/5 odds-on to replace Mr Bercow with Harriet Harman, the former Deputy Labour leader, next at 4/1, followed by her Labour colleagues Rosie Winterton on 8/1 and Chris Bryant on 10/1. Scot Eleanor Laing, another Deputy Speaker, was also on 10/1.