Boris Johnson has failed in his attempt to bring his new Brexit deal to the UK parliament for a straight "yes or no" vote on Monday.
The House of Commons Speaker John Bercow rejected the move on the grounds that the matter was considered in Saturday's emergency session. "It is clear that the motions are in substance the same," he said.
Bercow added that it would be "repetitive and disorderly" to allow the same motion to be debated today.
On Saturday lawmakers voted to delay approval for the deal until the accompanying legislation has been passed, to prevent a no-deal departure in the event that laws are not passed in time.
The prime minister struck a revised divorce agreement with the EU last week ahead of the UK's scheduled departure date of October 31.
The deal must be passed by both UK and European parliaments in order to take effect. But its ratification is on hold amid more British political turmoil.
Earlier, a spokesman for the prime minister said the government would stop a vote on the deal if lawmakers tried to make changes to it. The Labour opposition wants the agreement altered to make the UK more closely aligned with the EU than is envisaged, and to put it to a second referendum.
Government critics accuse it of trying to ram through the agreement without allowing enough time for MPs to examine it in detail.
The British government has said its Brexit bill, to implement the new agreement negotiated with the EU, will be published on Monday.
Jacob Rees-Mogg, the leader of the House of Commons, said the government wanted to have a second reading of the bill on Tuesday and that the lower house of parliament would have a final vote on the bill on Thursday.
Read more: Brexit Guide: Where are we now?
EU considers extension request
In another development, the European Parliament's Brexit Steering Group is recommending that MEPs do not hold their vote on the Brexit deal until it has been fully ratified in Westminster.
Meanwhile, the EU has been taking account of the British request for another Brexit extension. Parliament's lack of approval for the deal by Saturday obliged the prime minister to seek a delay.
Germany's foreign minister said on Monday that a "short, technical extension" could be possible if there were "problems in Britain with the ratification". Heiko Mass said he hoped the House of Commons would show "the necessary responsibility... to achieve an orderly Brexit".
The German economy minister Peter Altmaier has also said there would be "no problem" to approve an extension of "a few weeks". However, a spokesman for Chancellor Angela Merkel said the decision would be up to the EU27 countries.
The UK's Brexit minister Steve Barclay has said there is still a risk that the UK could leave the European Union without a deal at the end of the month.
"The risk of a no deal remains," he told a parliamentary committee on Monday. "The EU 27 may not agree an extension and the House (of Commons) has not to date agreed a deal, and so that risk remains pertinent and it is important we prepare for it."
Battle for numbers
Boris Johnson's deal alters previously-negotiated arrangements for Northern Ireland, and envisages a cleaner break for the UK with the EU than the accord struck by Theresa May.
The prime minister said earlier he would bring legislation forward early this week and has vowed to take the UK out of the European Union on October 31.
UK foreign secretary Dominic Raab told the BBC on Sunday that he is "confident" that the government will pass the deal Johnson struck up with EU leaders last week, saying the UK will leave by the October deadline.
"We believe we've got the numbers and we'll keep talking to the DUP and see if there's further reassurances that can be provided," Raab told the BBC's Andrew Marr show.
Northern Ireland's Democratic Unionist Party (DUP) have said they will vote against the deal, but Conservatives have in the past relied on their support for a working majority in Parliament.
Johnson sent an unsigned letter to European Council President Donald Tusk on Saturday night requesting a Brexit delay until the end of January, as required by legislation that was passed in September that was meant to prevent a no-deal Brexit.
Tusk said he had received the request for an extension, and EU ambassadors met and took note of the request.
Johnson sent a second, signed letter arguing that an extension would be damaging, stating that the process must be brought "to a conclusion", but Johnson will have to face off with lawmakers in Parliament this week.
Shadow Brexit secretary Keir Starmer said an amendment calling for a second referendum is "inevitable".
"There will be an amendment on a referendum, whether there will be detailed amendments put next week for the whole of the referendum I don’t know. There’s lots of discussions going on," he said on the BBC's Andrew Marr show.
Starmer told the BBC that the Labour party is poised to back a second amendment as well, arguing that Johnson's deal should be considered by the British public.
"Whether it’s this deal or any future deal it’s got to go back, so the public can say, ‘do you want to leave on these terms?’ If so then we do. If not, we remain," Starmer said.
Labour shadow chancellor John McDonnell also said a second referendum amendment was inevitable and said that the people should have a say on the deal.
Raab called the Labour party plans to back a second referendum "a breach of faith with the voters".