Sam McBride: A day which is likely to have profound political implications

On anything approaching a normal day of business at Stormont, an emergency attempt to stop an overspend of half a billion pounds on a runaway energy scheme would dominate proceedings. Today, that will receive enormous attention, but will be just one element in a play of three acts.

The first item of business will be the formal call for a re-nomination for first minister and deputy first minister.

Assuming that Sinn Fein sticks to its uncompromising rhetoric, that will be the formal confirmation that the first Executive has fallen apart since the DUP and Sinn Fein took over almost a decade ago.

Having happened once, that development could have profound implications for the future. When the first post-Agreement Executive under the UUP and SDLP’s leadership fell in 2000 it heralded a yo-yo period where devolution was suspended a total of four times in two years, the last of which saw no local Executive for four and a half years.

The next critical item on the order paper is Simon Hamilton’s emergency legislation to slash the costs of the RHI scheme before the Assembly is dissolved and politicians find themselves at the mercy of a restless electorate.

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The draft Renewable Heat Incentive Scheme (Amendment) Regulations (Northern Ireland) 2017 - which were only emailed to the MLAs who will today be asked to vote on an issue of financial, political and contractual complexity at 7.42pm on Friday - are likely to provoke a mammoth debate.

Because there is no time limit on the debate of legislation, every one of the 108 MLAs (minus the Speaker) will have the opportunity to speak without limit on the issue - and to do so with absolute legal privilege, meaning that they cannot be sued for anything that is said.

Whenever that finishes, the final momentous item on the order paper is a Sinn Fein motion of no confidence in the Speaker, Robin Newton.

That proposal is without precedent at Stormont and is an indication of how rapidly - and utterly - the DUP-Sinn Fein detenté has been dashed to pieces in the space of just a few weeks.

Mr Newton is likely to find himself publicly forsaken by everyone but the DUP. Yet he has given no indication that he will go without being pushed.

On Friday evening the East Belfast veteran wrote a four-page letter to MLAs defending his handling of the shambolic Assembly sitting on December 19 where for 20 minutes he faced open rebellion from across the chamber, with innumerable points of order being raised over his decision to allow the First Minister to speak in that capacity despite the withdrawal of permission from Martin McGuinness.

The DUP have a decision to take about whether to table a petition of concern to formally block the motion. Doing so would be largely meaningless - and would actually reinforce the already damaging perception that Mr Newton remains too close to his party - but it would be a symbolically aggressive pre-election act, demonstrating that the DUP has the power in the Assembly to veto anything of which it disapproves.

The likelihood is that the Secretary of State will call an election either this evening or tomorrow.

If that happens, this eight-month Assembly is likely to have gone out with multiple bangs rather than with a whimper. But when will it be back?