Mr Bercow said parliamentary rules dating back to 1604 made clear that a government could not bring back the same or similar motion “ad infinitum” even though MPs keep rejecting it.
With just 11 days until Brexit is scheduled to take place, it means the Prime Minister has little alternative but to ask EU leaders for a lengthy delay of up to two years at a summit in Brussels on Thursday.
“Decisions of the house matter. They have weight,” the Speaker said. “It is a necessary rule to ensure the sensible use of the house’s time and the proper respect for the decisions which it takes.”
Critics of Mrs May’s deal on both sides of the Brexit debate cheered the shock announcement, with Brexiteers arguing the government should embrace a no-deal exit, while campaigners for a second EU referendum said the only way for the government to save its agreement was to accept putting it to the people.
The Commons Speaker blindsided ministers with his intervention yesterday afternoon, which means that without changes to the Brexit deal, a further vote cannot be held until a new parliamentary session begins.
The Prime Minister’s official spokesman said: “The Speaker did not warn us of the contents of the statement or indeed the fact that he was making one.”
Downing Street gave no official response, but shortly after Mr Bercow’s statement, the Solicitor General Robert Buckland said the UK was in the grips of a “major constitutional crisis” and warned that the government could be forced to prorogue parliament, asking the Queen to bring the current session to an end months early.
“There are ways around this – a prorogation of parliament and a new session – but we are now talking about not just days but hours to 29 March,” Mr Buckland said. “Frankly we could have done without this, but it’s something we’re going to have to negotiate with and deal with.”
Citing rules set out in the parliamentary handbook Erskine May, Mr Bercow told MPs: “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 March 12, this would be entirely in order.
“What the Government cannot legitimately do is resubmit to the House the same proposition - or substantially the same proposition - as that of last week, which was rejected by 149 votes.”
Any change must be “not different in terms of wording but different in terms of substance” and would need to be “in the context of a negotiation with others outside the UK”, Mr Bercow added.
While the government had signalled it wanted to bring back the deal for a third vote today or tomorrow, Downing Street said on Monday that it wouldn’t do so until it was clear that it could win.
A number of leading critics of the deal, such as European Research Group chairman Jacob Rees-Mogg, said they were now willing to back it to avoid a lengthy delay.
However, in his Telegraph column, Boris Johnson said it was impossible for “anybody who believes in Brexit” to back the deal in its current form, and 23 Eurosceptic Tory MPs also said they were still opposed.
There is also no sign of the government’s DUP shifting their stance to support the deal despite talks between the party and ministers over the weekend.
“The deal can’t be brought back,” Mr Blackford told journalists after the Speaker’s statement. “If there’s an extension, you have to ask - for what purpose?
“There has to be a purpose to it, and ultimately we have to reach the conclusion that we need to put this back to the people. That’s the right thing to do.”
Liberal Democrat leader Sir Vince Cable said the Prime Minister would be forced to “change the deal in a fundamental way or face the other alternative, which is taking this back to the people with the option to remain”.
Mr Blackford added that if the government tried to push ahead with a no deal Brexit, parliament would seek to have Article 50 revoked. “In such a scenario, we have to be able to apply a handbrake,” he said.