LONDON (Reuters) - With a wordy speech invoking a 17th-century precedent, and a cold stare aimed at stunned ministers, the grandiose Speaker of Britain’s parliament cast Prime Minister Theresa May’s Brexit strategy into chaos.

Less than two weeks before Britain is due to leave the European Union, John Bercow warned on Monday that May would be unable to hold a third vote on the same Brexit deal that has already been crushed twice by lawmakers.

The ruling blindsided the government, trashing May’s plan to secure last-minute approval from parliament this week, and putting Bercow, a man who unashamedly revels in the importance of his office, at the centre of Britain’s Brexit drama.

As the government’s solicitor-general, Robert Buckland, noted wrily after Monday’s ruling: “This speaker has made his name for being interventionist and innovative in many ways.”

In a country with no written constitution, and a parliament ruled by convention and precedent that can be changed and re-interpreted at any time, the person who heads the House of Commons wields significant power.

Bercow’s put-downs of misbehaving lawmakers, ranging from headmasterly to acid, have travelled around the world in viral video clips, along with his elongated, mangled cries of “Order! Order!”.

But since May’s Conservative Party lost its majority in 2017, and as Brexit has become entangled in the weeds of parliamentary procedure, Bercow’s influence has soared.

“NO FRIEND TO GOVERNMENT”

More than any recent predecessor, the 56-year-old, who says he voted in 2016 for Britain to remain in the EU, has championed parliament against the executive.

Monday’s ruling was just one in a line of recent decisions that infuriated ministers and delighted those who want to increase parliament’s role in scrutinising the process of leaving the EU.

“It’s fair to say that the Speaker has been no friend to government on any of this,” one official from May’s office said earlier this year, after Bercow permitted a move by a pro-EU lawmaker that prevented the government running down the Brexit clock to impose its will on parliament.

His every move now carries political weight, right down to the order in which lawmakers are called to speak, with members of the government complaining that he has given precedence to its critics in key debates.

Bercow has occupied the throne-like speaker’s chair, positioned between government and opposition benches in parliament, since 2009. Refereeing debates and ruling on procedure, he has made friends and enemies in roughly equal measure.

Speaker of the House John Bercow gestures as he speaks after tellers announced the results of the vote Brexit deal in Parliament in London, Britain, March 12, 2019, in this screen grab taken from video. Reuters TV via REUTERS

“I say to very senior members who, from a sedentary position, are chuntering really very inanely: Do try to grow up!” he declaimed during one typically rowdy debate on Brexit.

The speaker’s role is politically impartial, meaning Bercow has given up his allegiance to May’s Conservative Party.

“FEW FRIENDS”

But critics say he has swung too far the other way, favouring the opposition Labour Party by frequently allowing them to drag reluctant ministers to parliament to explain policy mishaps on everything from welfare to transport.

“He doesn’t have any friends in the Conservatives. Well, no one of note anyway ... So he only really has ‘red’ (Labour) friends,” said a veteran member of the Conservative Party who asked not to be named.

In January, pro-Brexit lawmaker Adam Holloway accused Bercow of having an earthy anti-Brexit sticker on his car. Bercow said the car was his wife’s, adding: “That sticker is not mine, and that is the end of it.”

Bercow has overseen a considerable programme of reform and modernisation within the 800-year-old parliament, but beyond the quirkiness, his conduct outside the chamber has also attracted scrutiny.

During his nine-year term, Bercow has survived an outcry over expense claims - including costly use of official cars and overseas trips - and has faced allegations of bullying from former members of staff, which he has denied.

An investigation published in 2018 said the lower house of parliament had allowed a culture of bullying and sexual harassment to thrive, and that, to restore confidence, its top officials may need to be replaced.

Labour lawmaker Margaret Beckett dismissed calls for Bercow to go, saying that “the constitutional future of this country ... trumps bad behaviour”.

In the furore following his statement on Monday, he batted away questions and criticism with typical composure.

“I am not in the business of panicking myself,” he said. “I think I can safely say that I have never lost a wink of sleep over any work-related matter. There is no merit or purpose in doing so.”