Northern Ireland is heading for a snap election after Sinn Fein triggered the implosion of the powersharing executive by declining to re-nominate a deputy first minister.
Barring a highly unlikely u-turn by the republican party, the institutions will now fall at 5pm on Monday and Northern Ireland Secretary James Brokenshire will be legally obliged to call the election.
At the start of Assembly business on Monday, Sinn Fein refused to replace Martin McGuinness as deputy first minister, a week after he quit citing irreconcilable differences with his long term Democratic Unionist partners in government.
His resignation was precipitated by the renewable heat incentive (RHI) scandal - a botched eco-scheme set to cost Stormont £490 million - but that row has also reignited a range of other bitter disputes dividing the coalition.
Sinn Fein MLA Michelle O’Neill told the Assembly: “The DUP have treated these institutions and sections of the community with contempt and arrogance.”
She added: “Today Sinn Fein will not re-nominate for the position of deputy first minister.”
Ms O’Neill said Sinn Fein would only return to government if there was “real and meaningful change”.
Mr McGuinness’s resignation automatically removed DUP leader Arlene Foster from her position as first minister - as executive structures dictate one cannot govern without the other.
On Monday the DUP renominated Mrs Foster to the post. That was rendered meaningless by Sinn Fein’s subsequent refusal to renominate its own incumbent at the head of the executive.
Speaker Robin Newton said both ministers needed to be in post for their office to function.
“These requirements have not been satisfied today and the offices of the first minister and deputy first minister must remain vacant,” he said.
Ahead of the key Assembly session at Parliament Buildings in Belfast, Mrs Foster said the electorate did not want or need an election.
She accused Sinn Fein of triggering a poll because they did not like the outcome of last May’s vote.
“They have forced an election that risks Northern Ireland’s future and stability and which suits nobody but themselves,” she said.
Theresa May phoned Mrs Foster and Mr McGuinness early on Monday in a last-ditch effort to prevent the collapse of the devolved administration.
The Prime Minister’s official spokeswoman said Mrs May wanted to make sure Northern Ireland has “a voice” in the run-up to the start of EU withdrawal talks - expected to be triggered by the end of March with the invocation of Article 50 of the European Union treaties.
The Stormont Assembly will limp on until it is formally dissolved. An election is likely in late February or early March.
The failed reappointment process came at the opening of a full day of Assembly business during which a number of elements of the political crisis will be debated.
Emergency proposals aimed at reducing the RHI overspend are being proposed by DUP economy minister Simon Hamilton while Sinn Fein will also table a motion of no confidence in DUP speaker Mr Newton.
He has been under intense political pressure over his handling of a recalled Assembly session to debate RHI before Christmas.
The Speaker has also been forced to defend himself against conflict of interest accusations in regard to his handling of Assembly exchanges on a controversial charity in his east Belfast constituency.
The devolution meltdown has cast a shadow of uncertainty over a series of big ticket Stormont executive plans.
One of those is a payment scheme for households losing out under the UK Government’s so-called “bedroom tax” when it is introduced in Northern Ireland next month.
After Sinn Fein announced it would not replace Mr McGuinness, DUP Communities minister Paul Givan secured the necessary Assembly approval to roll out the bedroom tax scheme.
Ulster Unionist leader Mike Nesbitt was gearing up for the election.
“It is referendum time. You can have more of the same or you can have change. We are for change.”
Mr Brokenshire said: “No one should underestimate the challenge faced to the political institutions here in Northern Ireland and what is at stake.
“While it is inevitable that debate during an election period will be intense, I would strongly encourage the political parties to conduct this election with a view to the future of Northern Ireland and re-establishing a partnership government at the earliest opportunity after that poll.
“The Government continues to stand firmly behind its commitment to the Belfast Agreement and its successors, and our responsibilities to safeguard political stability.
“We will continue to do all that we can to find a way forward and secure the continuation of devolved government and I will make a further statement in Parliament tomorrow.”