The special sitting has been convened for Saturday 19 October to deal with the fallout from the European council summit taking place in Brussels two days before, where European leaders are expected to reject the UK’s government’s proposals for resolving the Irish backstop.
News of the rare sitting comes as UK Prime Minister Boris Johnson meets his Irish counterpart, Leo Varadkar, on Thursday in a last ditch bid to try and break the deadlock on a Brexit deal, while continuing to insist the UK will leave on 31 October with or without an agreement.
The meeting as a group of Conservative MPs demanded assurances from Johnson that he will not take the party into the next general election - whenever it comes - on a straightforward promise to leave with no deal.
It is unusual for the UK parliament to sit at a weekend, although the move does not prevent it from meeting to debate the Council conclusions on subsequent days.
In fact, the UK’s House of Commons has only sat on Saturdays four times since 1939. Three of those sittings were prompted by way or military conflict: 2 September 1939 (the day before the outbreak of the second world ward); 3 November 1956 (the Suez crisis); and 3 April 1982 (the invasion of the Falkland Islands).
Options for debate will range from leaving without a deal, to calling Brexit off altogether with every possible permutation in between.
“Brexit will remain the defining political issue of our time, with the prospect of a decade or more of bad-tempered negotiations, internal political rows, and uncertainty for business and citizens” Former UK Europe minister, Denis MacShane
Elsewhere, in a stormy Brexit debate in the European Parliament on Wednesday, former Belgian prime minister Guy Verhofstadt, the European Parliament’s Brexit Coordinator, accused Johnson of treating those seeking to prevent a no-deal Brexit as "traitors, collaborators and surrenderers".
The Belgian MEP said, "The reason this is happening is very simple. It is a blame game. A blame game against everybody - against the EU, against Ireland, against Angela Merkel, against the British judicial system, against Labour, against the Lib Dems, even against Theresa May.”
"The only person who is not being blamed is Boris Johnson apparently. All the rest are part of the problem."
Chief EU Brexit negotiator Michel Barnier said the EU needed workable solutions "today not tomorrow" and questioned the viability of the UK's proposals to give the Northern Ireland Assembly a veto over whether it aligned with EU single market rules for goods from 2021 onwards and whether to diverge from them in the future.
However, Barnier did confirm the two sides were looking at "a more important role" for the Northern Irish political institutions.
“In the real world, Brexit cannot be concluded on 31st October. However, on Brexit, the Conservative Party deals only in dreams and delusion” Former British Conservative MEP Brendan Donnelly
European Commission President Jean-Claude Juncker told MEPs during the plenary debate in Brussels that while he would "not exclude" a deal in the coming days, progress had been limited.
The “never-ending” saga of Brexit was also the subject of a high-level debate at the Federal Trust in London on Tuesday with contributions from former Europe minister Denis MacShane, constitutional expert Dr Andrew Blick from Kings College London and former Conservative MEP Brendan Donnelly.
In a comment for The Parliament Magazine, MacShane argued that despite attempts to bring the Brexit issue to a definitive conclusion, parliamentary and electoral arithmetic in the UK meant there was little prospect of an end in sight.
“Brexit will remain the defining political issue of our time, with the prospect of a decade or more of bad-tempered negotiations, internal political rows, and uncertainty for business and citizens,” MacShane said.
Blick addressed the constitutional implications of the Brexit impasse, making the case for a written constitution to establish “agreed rules of the game” which could help resolve divisions and bring the UK together.
"It is a blame game. A blame game against everybody - against the EU, against Ireland, against Angela Merkel, against the British judicial system, against Labour, against the Lib Dems, even against Theresa May. The only person who is not being blamed is Boris Johnson apparently" Guy Verhofstadt, the European Parliament’s Brexit Coordinator
“We can hardly rely on the decisions of a 93-year-old monarch as the last line of defence against abuses of our democracy” Blick said in respect of the decision – subsequently held to be unlawful – to prorogue the UK parliament in September.
“The problem is that in Britain today we have a culture in which many leading politicians seem to think it is acceptable to flout constitutional conventions, while voters appear to be ready to endorse this behaviour at the ballot box,” Blick added.
Donnelly argued that only a government of national unity could stop the UK crashing out of the EU on 31 October arguing, “In the real world, Brexit cannot be concluded on 31st October. However, on Brexit, the Conservative Party deals only in dreams and delusion.”
"Boris Johnson plays to the dreamers and deluded in his Party. Without them, there would be no Conservative Party,” Donnelly said.
The UK put forward fresh proposals for a Brexit deal last week, but so far, the reaction from the EU has not been encouraging. Johnson has said he remains "cautiously optimistic" about a deal.