John Bercow might just have provided a simple route to getting a Final Say on Brexit

John Bercow’s explosive ruling that Theresa May cannot put her Brexit deal to parliament a third time came as a shock to ministers. But it should not have done.

This scenario has been much discussed in recent days. Indeed, there was almost a vote on it last Thursday. The speaker chose for debate an amendment by Chris Bryant, a Labour MP who would like to succeed Bercow, saying that under parliamentary precedent, the same deal should not be the subject of another vote.

MPs might have rejected the amendment, so Bryant did not push it to a vote. If the Commons had blocked Bryant’s move, it might have made it harder for Bercow to issue today’s edict.

Last week, the view among Tory MPs was that “Bercow wouldn’t dare". But they should have known not to underestimate him.

Ministers, too, should have been warned after the speaker overruled the advice of his clerks during another Brexit controversy in January.

Bercow’s critics, and there are many of them at Westminster, will see his dramatic intervention as unashamed showboating by a man who loves the limelight. Yet the rule book and 300 years of precedent are on his side.

The government’s problem is that Erskine May, the Commons Bible, says that the speaker’s ruling is final. In private, ministers are already fulminating about him creating "a constitutional crisis". But if they attack Bercow in public, that hardly boosts their chances of persuading him to change his mind.

True, the speaker likes the sound of his own voice. He will be enjoying reports that his bellowing of "Order! Order!" – and his sometimes long-winded, pedantic rulings – have made him something of a media star on the continent.

Today’s landmark ruling will ensure Bercow is more than a footnote in the history books.

He originally promised to serve a nine-year term, which expired last summer, but decided to stay on for the Brexit debates. Although elected as a Tory MP before becoming speaker, Tories suspect he has travelled to the other end of the political spectrum. He voted Remain in the 2016 referendum and is accused by Tories of anti-Brexit bias. But they could not remove him without Labour’s support – which, inevitably, was not forthcoming.

Although criticised for his handling of allegations that Commons staff have suffered harassment and intimidation, in many ways Bercow has been a good speaker. He has championed the rights of backbenchers – ostensibly the reason for today’s ruling, because debating the same proposition over and again would waste their time. His biggest change was to grant backbenchers many more urgent questions, forcing ministers to face a Commons grilling at short notice on topical issues, problems and crises. This has raised parliament’s profile.

The best brains in the government and Whitehall will now work overtime to find a way round Bercow’s decision. To keep it in context, it was far from certain that Theresa May would have gone ahead with a third meaningful vote on her deal this week. Next week, just before the UK’s scheduled departure from the EU and after this week’s EU summit had approved a long delay, was probably more likely.

May will now have to present something different to the Commons for Bercow to allow any vote on her deal next week. He made clear that an agreement with the DUP or new legal advice from the attorney general Geoffrey Cox would be unlikely to cut it.

EU leaders will now be even more bemused by May’s predicament and are unlikely to do her any favours by tweaking the withdrawal agreement. Jean Claude-Juncker, the European Commission president, offered reassurances last week, but the deal was still rejected by 149 votes.

There is one way May could pass the Bercow test. She could propose making her deal conditional on it being approved in a Final Say referendum. That really would be different. An amendment to this effect from the Labour backbenchers Peter Kyle and Phil Wilson is already on the table. If May is so confident her deal is a good one, why not let the people decide?