The speaker of Britain's parliament says the government cannot propose a vote that is substantially the same as one that has already been defeated twice.
British Prime Minister Theresa May's Brexit plans have been thrown into turmoil after the speaker of parliament said she could not put her divorce deal to a new vote unless it was re-presented in a substantially different form.
In comments that have blindsided May's office, Speaker John Bercow says the government could not bring forward proposals for a vote in parliament that were substantially the same as had already been defeated twice before, in January and last week.
Speaker of the House has told parliament that Theresa May can’t bring her Brexit divorce deal back for another vote by MPs, unless there are actual changes to it. @SBSNews
— Ben Lewis (@benlewismedia) March 18, 2019
The ruling put Britain on a knife edge - Brexiteers seeking a complete break from the EU see a "no-deal" exit as now more likely while others think May might put off Brexit beyond the set March 29 departure date, if the EU approves.
One of the government's senior law officers, Solicitor General Robert Buckland, said: "We're in a major constitutional crisis here".
He told the BBC that one way to bring May's deal back for a vote in the House of Commons could be prorogation - ending the parliament session prematurely and starting a new one.
The pound fell to its day's low against the euro and the dollar.
According to precedents stretching back to 1604, parliamentary rules say that substantially similar proposals cannot be voted on in the House of Commons more than once during the same session of parliament.
Bercow said on Monday that his ruling should not be considered his last word and the government could bring forward a new proposition that was not the same as those already voted upon.
The government said negotiations on a deal were continuing with MPs from Northern Ireland, who prop up May's minority government and have opposed her withdrawal accord so far.
"This is my conclusion: if the government wishes to bring forward a new proposition that is neither the same, nor substantially the same as that disposed of by the house on the 12th of March, this would be entirely in order," Bercow said.
"What the government cannot legitimately do is to resubmit to the House the same proposition or substantially the same proposition as that of last week which was rejected by 149 votes," he said.
However Kwasi Kwarteng, a Brexit minister, told parliament the government intended to seek an extension to the Brexit departure deadline, which he expected the EU to decide on at a summit this week.
The head of the 2016 referendum campaign to leave the EU, Matthew Elliott, said he expected MPs to "see sense" and pass May's deal by March 29.
Bercow's ruling was welcomed by eurosceptic MPs in May's Conservative party who have rejected her deal, because the Speaker's move seemed to increase the likelihood of Britain leaving the EU without a deal.
May's withdrawal deal negotiated with the EU last year was seen by Brexiteers as leaving Britain too closely aligned to the EU while depriving it of voting rights in the bloc.