The Scottish Greens were the “glue holding stable government together,” the party’s co-convenor has claimed. 

Lorna Slater told the BBC’s Good Morning Scotland that she was “more disappointed than angry”  at Humza Yousaf for scrapping the Bute House Agreement, and said she expected to see the SNP “roll back on their climate commitments.” 

“And that makes me heartbroken for Scotland's young people and future generations,” the ex-minister said. 

READ MORE: Yousaf 'absolutely' not resigning ahead of no confidence vote

During the interview, the Lothian list MSP appeared to suggest that her colleagues could be persuaded to back Mr Yousaf at next week’s vote of no confidence.

Ms Slater said Green MSPs had taken the decision not to support the First Minister but the group could “have that conversation again.” 

“Nobody has reached out to us in any way to try and change our minds,” she said. 

Ms Slater said the First Minister only had himself to blame: “We had been a stable progressive government. And as things unravel so rapidly, I think it will become clear that the Greens were the glue holding stable governance together in Scotland.

“Whether he could hold together a government now, I don't know. 

“But the agreement between the Greens and the Scottish Government was in it is heart a confidence and supply agreement. He broke the deal.”

She claimed Mr Yousaf “felt obliged to end the Bute House Agreement because he had lost control of the right wing of his party.”

Ms Slater said: ”He had done the maths and realise that he had more rebels than he could cope with. So he is being forced by events, I expect, to move suddenly to the right.”

A senior Green source told The Herald the news had not just surprised them but SNP MSPs too.

"We've had a steady stream of senior SNP people coming downstairs [to the Green party offices in Parliament], some of them clearly emotional, because a lot of time has been spent with our MSPs and their MSPs and ministers, building up a progressive working relationship as part of a pro-independence Scottish Government."

"There's been surprise and distress, I don't think that would be too strong a word," they added.

"It shows the great strength that there was between the two parties and the working relationship. It's very, very sad and disappointing that this has happened. I don't understand the strategy of this."

READ MORE: Scottish Labour to trigger vote of no confidence in SNP government

Next week, MSPs were due to debate and vote on a motion of no confidence in Patrick Harvie tabled by Alba.

There has been some speculation several SNP MSPs would have broken the whip and either voted against the Green or abstained.  Though the SNP chief whip Rona Mackay has insisted that none of her members supported the motion.

Speaking to the PA news agency, Mr Harvie said Mr Yousaf “very clearly” did not have the confidence of parliament.

“We said the responsibility of the decision is on him. He needs to bear the consequences of that reckless and damaging decision.

“I think it’s pretty clear he’s not the person who is going to be able to bring together a majority of parliament.”

Asked if there was any way back for Mr Yousaf in terms of working with the Greens, he said the First Minister had “broken trust”.

READ MORE: Yousaf cancels independence speech amid leadership crisis

Mr Harvie added: “He still hasn’t really given any clarity on why he made such a dramatic U-turn and broke a promise on which he was elected as First Minister.

“So it’s very difficult to see how you can have a conversation that leads to a constructive outcome on the basis of that lack of trust.”

Speaking to journalists in Dundee, Mr Yousaf said he did not regret the ending of the Bute House Agreement but that it was not his intention to upset the Greens.

He said he had written to the party's co-convenors, as well as the leaders of all Holyrood's parties to discuss working together on an issue-by-issue basis.

He said he “really valued the contribution” of Mr Harvie and Ms Slater in government. 

“That upset and anger, that wasn’t meant from me, and I look forward to hopefully a response from Patrick and Lorna to the letter I intend to write them in the coming days.”