An attempt to amend a bill which its opponents say gives too much power to individual Stormont ministers has failed after MLAs from four of the five Executive parties opposed it.
DUP MLAs disregarded the advice of their party's former special adviser, barrister Richard Bullick, who has argued that they are "sleepwalking into making profound constitutional amendments" and shedding gains that the party negotiated in the 2006 St Andrew's Agreement.
The amendment was defeated by 73 votes to 10 with only the Ulster Unionists, TUV leader Jim Allister, and former DUP MLA Jim Wells supporting it.
People Before Profit and the Green Party did not back the amendment, although they will oppose the bill in a final vote on Tuesday.
Neither First Minister Arlene Foster, nor deputy First Minister Michelle O'Neill, who proposed the legislation, were present for the debate.
Stormont sources admitted to the Belfast Telegraph that fast-tracking such complex legislation through the Assembly was "far from ideal".
They denied that the bill would mean dangerous solo runs by individual ministers but believed it would "help business flow better". They acknowledged Mr Bullick's expertise on the issue, but said that the Executive's most senior legal advisers disagreed.
"It's a highly technical argument, so there is much confusion," a source said. "Probably, about only 15 people in the whole of Northern Ireland understand what's going on.
"Richard Bullick knows his stuff inside out but the Executive's most senior legal advisers disagree with his interpretation. The only definitive answer will be when the whole matter is tested in court."
The bill seeks to clarify what constitutes a cross-cutting issue that requires the consideration of the whole Stormont executive.
It is a response to the 2018 Buick court judgment, when judges ruled that the granting of planning permission for a contentious waste incinerator plant in north Belfast was unlawful.
UUP MLA Doug Beattie argued that the Executive Committee (Functions) Bill was an "extremely complex" piece of legislation with "far-reaching" consequences, and should be paused.
"The reality is, it needs more scrutiny," he said. "This bill intends to give ministers more power and that can be abused.
"I don't want to see any minister abusing their power, and the way to stop them either deliberating or accidentally abusing their power is to have a scrutiny mechanism which is in the Executive already."
But DUP MLA Christopher Stalford rejected the suggestion the bill would allow solo runs, such as the move by the late Martin McGuinness to abolish the 11-plus in 2002 when he was Education Minister. "Let me be very clear, under St Andrews and under this bill today, such a decision could not be made by a minister on a solo run. It is simply not true to say that it could," Mr Stalford said.
"We pushed hard to have this issue addressed at St Andrews, and we will fully maintain the protections which prevent government ministers from doing such things without the agreement of Executive colleagues.
"Any suggestion that this bill would diminish this is a fundamental misunderstanding of the bill which we have been considering."
Mr Wells said that DUP MLAs had "been whipped to within an inch of their life to vote for something that many of them are extremely unhappy with but have been told they have to vote for".
The South Down MLA said: "There is a conflicting legal advice on this, but the crucial legal advice comes from one of the architects of the St Andrews Agreement, Richard Bullick.
"If there is doubt between those who think that this will stop solo runs and those who think that it will facilitate them, the obvious thing to do is to postpone the further consideration stage of the bill.
"It is not to try to railroad through something as important as this at the end of an Assembly term and with 24 hours' notice to table amendments."