Opposition leaders will hold a symbolic meeting in the proposed venue for a ‘rebel’ parliament following talks on how to stop a no deal Brexit and prevent Boris Johnson from suspending the House of Commons.
The gathering on Tuesday afternoon comes as the Prime Minister again refused to rule out proroguing parliament to ensure the UK leaves the EU with or without a Brexit deal, calling on all MPs to “respect the will of the people” and deliver the result of the 2016 referendum.
Labour leader Jeremy Corbyn will convene a meeting of opposition leaders at Westminster on Tuesday morning to discuss parliamentary tactics to stop a no-deal outcome.
Later, leading opposition figures including the SNP's Ian Blackford and Liberal Democrat Jo Swinson are expected to be joined at Church House by a number of Conservative MPs committed to stopping a no deal Brexit, in a warning to an administration that has a working majority of one.
Church House, the headquarters of the Church of England located next to Westminster Abbey, hosted meetings of parliament when the Commons suffered bomb damage.
It was suggested as the venue for a English Civil War-style rebel parliament by the Tory leadership candidate Rory Stewart, who said he would “work with colleagues simply to organise another parliament across the road” if the Commons is suspended to prevent votes blocking a no-deal Brexit.
Speaking at the close of the G7 summit in Biarritz on Monday, Mr Johnson was repeatedly challenged to rule out suspending parliament, but refused to do so.
"I think it's the job of everybody in Parliament to get this thing done,” he told reporters at the summit in southwest France.
"I think it's what the people want - I also think, by the way, it's what our friends and partners on the other side of the Channel want - they want it over.
"They are very enthusiastic about getting on with the future. They regard Brexit now as an encumbrance, an old argument. They want to talk about the new partnership that we're going to build."
Asked about attempts by opposition MPs to block a no-deal Brexit, Mr Johnson added: "I think this is really a matter for parliamentarians to get right ourselves.
"I think that people have just about had enough of this conversation. And I think they are yearning for a moment when Brexit comes off the front pages.
"But that can only happen when we come out of the EU on October 31."
A senior government official underlined the message, telling journalists in Biarritz: “The prime minister has been repeatedly clear that parliamentarians and politicians don’t get to choose which public votes they respect.”
The Prime Minister reiterated his determination to stop a plan to collapse the government and usher in a caretaker administration, potentially lead by Labour leader Jeremy Corbyn.
"One of my many missions in life is to protect the people of this country from the appalling consequences of a Labour government,” Mr Johnson said.
"And it's clear from what Jeremy Corybn is now saying that not only if he were in power would he put up taxes on virtually everything from income to pensions to inheritance to property, not only would he align himself with some of this country's most intractable and difficult foes, but he would also renege, reject, revoke the mandate of the people.
"And I cannot think of anything worse for democracy or for trust in politics and I very much hope that does not happen."
The Prime Minister said he was “marginally more optimistic” following a weekend of talks with leading EU figures on the margins of the summit, including French President Emmanuel Macron and German Chancellor Angela Merkel
But he warned journalists to “remember that all statistical estimates that I give about the chances of a deal - whether they are expressed in odds of millions to one, or getting closer, or hotter or colder, or whatever - they all depend exclusively on the willingness of our friends and partners to compromise on that crucial point and to get rid of the backstop and the current withdrawal agreement."
Mr Johnson added: "I think that our German friends and our French friends have certainly listened very carefully to what we have had to say.
"It all depends on how seriously they wish to get a deal."
Strains between opposition parties working together to stop a no-deal Brexit were on show again on Monday, with the Liberal Democrat leader Jo Swinson writing to Mr Corbyn to warn him that a ‘neutral’ figure may have to be found to lead a caretaker government.
“We cannot allow party politics to stand in the way of finding a solution that works to prevent the national crisis approaching us,” she wrote.
Meanwhile, it was reported that the head of the Church of England, Archbishop of Canterbury Justin Welby, has held talks about leading a citizens’ assembly with the aim of avoiding a no-deal Brexit.