Speaker John Bercow has thrown the UK’s Brexit plans into further confusion by ruling out another vote on the PM’s deal unless MPs are given a new motion.
In a surprise ruling, he said he would not allow a third “meaningful vote” in the coming days on “substantially the same” motion as MPs rejected last week.
With 11 days to go before the UK is due to leave the EU, ministers have warned of a looming “constitutional crisis”.
The UK is currently due to leave the EU on 29 March.
Theresa May has negotiated the withdrawal deal with the EU but it must also be agreed by MPs.
They have voted against it twice, and the government has been considering a third attempt to get it through Parliament.
Mr Bercow cited a convention dating back to 1604 that a defeated motion could not be brought back in the same form during the course of a parliamentary session.
He said the second vote on the prime minister’s deal last week was “in order” as it was substantially different to the first, but any further votes must pass the “test” he set out to be allowed.
The BBC’s political editor Laura Kuenssberg said the speaker’s intervention does not stop Brexit from happening, but it makes it “extremely unlikely” that the government will put another vote on the deal to Parliament this week.
She said this makes it less likely the prime minister will ask EU leaders at a summit this week for a short extension – which Mrs May had said she would do if her deal got through Parliament.
This in turn makes it more likely there will be a longer delay to Brexit, she added.
She said: “The conclusion that most people in Westminster would reach from that means that we’re heading – it’s likely – towards a closer relationship with the European Union, a softer Brexit than the one Theresa May has set out.”
However, she added: “That said, the government does believe that, although they’re not clear about what it might be yet, there is a way round this complication – but it is another significant obstacle for Number 10 tonight and it has, in the words of one senior official, made things significantly more complicated.”
Mr Bercow’s statement appeared to take Downing Street by surprise, with the prime minister’s official spokesman saying it had not been warned of its contents “or indeed the fact that he was making one”.
Later, a Number 10 spokesman said the statement had been noted and required “proper consideration”.
The role of the speaker, who is the highest authority of the House of Commons, includes controlling debates, calling MPs to speak and choosing which amendments can be debated.
