Humza Yousaf's premiership is hanging in the balance after a turbulent day that saw his attempt at a leadership powerplay end in uncertainty over his own future.

Following an early morning meeting during which he told his two Scottish Greens ministers he would end the Bute House Agreement, his former political partners vowed to back a motion of no confidence in his leadership.

Lodged by Scots Tory leader Douglas Ross and announced during a rambunctious First Minister's Questions, the motion has the support of Scottish Labour, the Lib Dems and the Greens - giving the deciding vote to the Alba party's Ash Regan.

Ms Regan, described by former First Minister Alex Salmond, as now "the most important MSP in Scotland", was dismissed as unimportant by Humza Yousaf when she initially crossed the floor from his party to Alba.

READ MORE: Lorna Slater claims Humza Yousaf 'folded to pressure from the right' of the SNP

READ MORE: Ash Regan now 'most powerful' MSP in Holyrood

Ms Regan said: “I think it was long, long overdue and hopefully this signals a return to competent government but I’m very pleased to see that this will be the end of Green party extremism.

“I’m happy to listen to what the SNP have got to say, my door is open and I will support them on an issue-by-issue basis.

“My priorities are completely unchanged and that is: independence, women’s rights, child protection, protection of our key industries.”

Earlier in the day, Mr Yousaf held an unexpected cabinet meeting to tell colleagues of his decision to end the agreement founded by his predecessor Nicola Sturgeon in 2021.

An insider at the meeting said support for the move had been "unanimous" and MSPs had banged the table to show their approval.

Mr Yousaf said the immediate end of the deal marked a “new beginning” for his SNP minority Government.

Retribution from the Greens was swift, however, with Ms Slater issuing a coruscating statement accusing the First Minister of cowardice, a lack of fortitude and saying he could not be trusted.

The end of the deal comes amid growing tensions between the two pro-independence parties – with Greens left furious after the Scottish Government last week abandoned a key climate change target.

Greens were also unhappy at the decision to pause the prescription of puberty blockers to new patients at Scotland’s only gender services clinic for young people in Glasgow – a decision taken in the wake of the Cass Review in England and Wales.

But it was Mr Yousaf who called time on the deal, saying it had “served its purpose”.

During a press conference at Bute House, his official residence in Edinburgh, the First Minister said: “It is no longer guaranteeing a stable arrangement in Parliament, the events of recent days have made that clear, and therefore, after careful consideration, I believe that going forward it is in the best interest of the people of Scotland to pursue a different arrangement.

“That is why, following a discussion with my Cabinet this morning, I have formally notified Patrick Harvie and Lorna Slater that I am terminating the Bute House Agreement with immediate effect.”

He said the day marks a “new beginning for this SNP Government”.

But Ms Slater condemned the move, saying: “This is an act of political cowardice by the SNP, who are selling out future generations to appease the most reactionary forces in the country.

“By ending the agreement in such a weak and thoroughly hopeless way, Humza Yousaf has signalled that when it comes to political co-operation, he can no longer be trusted.”

Ms Slater accused the SNP of having “broken the bonds of trust with members of both parties” and said it had “betrayed the electorate”.

The Greens had planned to hold a vote on the future of the Bute House Agreement – which was signed when Nicola Sturgeon was first minister.

But before that could be held, the SNP acted to call time on the arrangement.

Ms Slater insisted the Green co-leaders had been “confident” their members would have backed staying in Government in the vote, and “continuing our work for Scotland”.

But some high-profile members of the SNP, including former leadership candidate Kate Forbes and party stalwart Fergus Ewing, have previously questioned the arrangement – prompting Ms Slater to claim the “most reactionary and backwards-looking forces within the First Minister’s party have forced him to do the opposite of what he himself had said was in Scotland’s best interests”.

She insisted: “By contrast, we as co-leaders of the Scottish Greens were prepared to put our own political careers on the line with our members, to defend our achievements in government, despite enduring all that SNP backbenchers and others threw against us. ”

Continuing her attack on the First Minister, Ms Slater added: “What a pity he didn’t have the fortitude or the bravery to do the same.”

Speaking about the SNP, she said: “If they can’t stand up to members of their own party, how can anyone expect them to stand up to the UK Government at Westminster and defend the interests of Scotland?”

In response to the end of the powersharing deal, Scottish Labour deputy leader Dame Jackie Baillie said: “This chaotic and incompetent Government is falling apart before our eyes.

“Humza Yousaf is too weak to hold his own Government together and he is too weak to deliver for Scotland.”

Mr Yousaf would not confirm if he will step down if a motion of no confidence in his leadership is successful.

Asked if Mr Yousaf would resigned should he lose the motion of no confidence, a spokesman said the issue was "hypothetical" and "the business of next week".

Should he stay on if a vote of no confidence is successful he would be in defiance of the will of the Scottish Parliament.

Ms Slater revealed details of the 8am Bute House meeting, saying she understood the First Minister had decided to end the BHA - having previously robustly defended the deal - due to "pressure from the conservative wing of the government".

She said: "It was clear to me that it was because of pressure from the conservative wing of his own party, from the right wing and the vested interests that have been putting pressure on our progressive cooperation agreement."

Asked for more details, Mr Harvie added: "Actually, I don't think it would be appropriate to disclose the specific detail of a private conversation," but added that the conversation had been "robust".

The MSP added that he had received "a number of very warm comments from SNP members who also feel disconcerted by this shock decision."