Opposition leaders have demanded that Boris Johnson reverse his decision to suspend Parliament or put it to a Commons vote.
In a rare joint statement, Labour, the SNP, the Liberal Democrats, Plaid Cymru, The Independent Group for Change and the Green Party condemned the Prime Minister’s move to prorogue Parliament for almost a month.
Mr Johnson said the suspension was necessary so he could put forward his Government’s new legislative agenda, and in order to do this through a Queen’s Speech, the current two-year session of Parliament must formally come to an end.
The statement came as the PM said both the UK and EU need to “step up the tempo” as the Government prepares to intensify talks with Brussels.
However, anti-no-deal MPs believe it is an attempt to shorten the amount of time they have to try to stop the UK leaving the EU without a deal.
In a statement, the opposition leaders said: “It is our view that there is a majority in the House of Commons that does not support this prorogation, and we demand that the Prime Minister reverses this decision immediately or allows MPs to vote on whether there should be one.”
The statement continues: “We condemn the undemocratic actions of Boris Johnson following his suspension of Parliament until October 14.
“There is no mandate from the public for a damaging no-deal Brexit. The Prime Minister is shutting down Parliament with the sole aim of stopping MPs from avoiding a no-deal Brexit.
“This will be the longest prorogation in recent history, and one that comes at a critical moment in the history of our respective nations and the Brexit process.
“Voters are being deprived of the opportunity to have their representatives hold the Government to account, make any key decisions, and ensure there is a lawful basis for any action that is taken.”
Leader of the House of Commons Jacob Rees-Mogg hit back at the PM’s critics, saying the outpouring of outrage it triggered was “phoney”.
It comes as backbench Tory rebels have started working with opposition MPs to try to force the Prime Minister not to take the UK out of the EU without a deal.
Former justice secretary David Gauke said next week will be crucial for MPs hoping to block a no-deal Brexit.
Speaking to BBC News, Mr Gauke said: “We are very concerned about what no deal is going to involve.
“It’s probably not in our interests to be very specific about what the proposals might be as to how we would do that.
“I think there are many of us who would be inclined to say that Parliament doesn’t need to take action for a while yet.
“But given the announcement from (Wednesday) that Parliament is only going to be sitting for a week next week and then really at the end of October, by which point it will be too late for Parliament to do anything effective.
“Then I do think we have to look at what our options are next week.”
He added: “The fact is there isn’t a mandate for a no-deal Brexit. It is not what was campaigned for in 2016.
“It is not what the public want according to opinion polls, only about a third of the public would support that and I think as the consequences of no deal become clear, that number may well fall.
“So I think Parliament does have a responsibility to act and it may well be that next week is the only opportunity for us to do so.”
Downing Street has said the UK’s team of Brexit negotiators will sit down with their EU counterparts twice a week during September “with the possibility of additional technical meetings, to discuss a way forward on securing a new deal”.
Mr Johnson’s chief Brexit sherpa David Frost met this week with the EU’s Article 50 Taskforce and agreed that talks would be intensified in the coming weeks.
Tory former chancellor Ken Clarke said he would be willing to vote against the Government in a confidence vote to try to stop a no-deal Brexit.
Asked if he would be willing to bring down the Government, Mr Clarke told ITV News: “If it’s the only way of stopping us plunging into the disaster of a no-deal Brexit, then yes."
Mr Johnson is facing legal challenges in London, Edinburgh and Belfast as the backlash to his decision to suspend Parliament for more than a month in the run-up to Brexit continued unabated.
He received a double blow as Scottish Tory leader Ruth Davidson and whip Lord Young of Cookham quit their posts on Thursday.
And the EU’s chief Brexit negotiator made it clear he was not ready to retreat on the issue of the Northern Ireland backstop, despite pressure from the Prime Minister.
Michel Barnier tweeted: “PM @BorisJohnson has said that the UK will leave the EU on 31 Oct. In all circumstances, the EU will continue to protect the interests of its citizens and companies, as well as the conditions for peace and stability on the island of Ireland. It is our duty & our responsibility.”
In her resignation speech, Ms Davidson highlighted “the conflict I have felt over Brexit”.
Lord Young, a Government whip in the upper house who served as a minister under Margaret Thatcher, was more direct, saying he was “very unhappy” with the Prime Minister’s decision to prorogue Parliament for an extended period as the October 31 deadline for Brexit looms.
Leading Brexiteer Mr Rees-Mogg hit back at critics, insisting the prorogation move was not intended to limit the time available for MPs to debate Brexit but will allow the Government to tackle other issues.
He said: “I think the outrage is phoney and it is created by people who don’t want us to leave the European Union and are trying very hard to overturn the referendum result and don’t want the benefits of leaving the European Union.”
He added: “Parliament wasn’t going to be sitting for most of this time anyway. This is completely constitutional and proper.”