Alba's only MSP will set out a list of demands for Humza Yousaf in exchange for her support in a confidence vote over the First Minister's leadership.

Ash Regan has said she wants Mr Yousaf to back her independence bill - among a raft of ultimatums - to secure her backing in a challenge levelled by the Scottish Conservatives.

Her party's leader, former First Minister Alex Salmond, said Mr Yousaf had inadvertently made Ms Regan the "most powerful MSP in the Scottish Parliament" as her vote could tip the balance of the result.

READ MORE: Humza Yousaf facing a vote of no confidence 

READ MORE: Scottish Greens accuse Humza Yousaf of cowardice

Speaking on Times Radio, he said she would "use that power very wisely indeed to progress the cause of independence, protect the rights of women and try to find a way to restore competence within the Scottish Government, which has been so badly lacking recently."

Ms Regan, who crossed the floor from the SNP to the Alba party, said she would write to the First Minister to outline three areas in exchange for her support.

Douglas Ross, leader of the Scottish Conservatives, said on Thursday at First Minister's Questions that he would progress a motion of no confidence in Mr Yousaf following the end of the Bute House Agreement.

Scottish Labour and the Liberal Democrats have said they would support the motion and insiders say it is likely the Scottish Greens will back it too.

Speaking to LBC earlier today, Ms Regan said she would work with the SNP on an “issue-by-issue basis” but her support in an upcoming confidence vote in Yousaf was conditional.

Mr Salmond said that Mr Yousaf had "managed to insult every opposition party".

The former SNP leader suggested a more sensible way forward would have been for Mr Yousaf to put the decision to the SNP membership.

Referring to "wee Patrick Harvie" the former FM, said the two Scottish Greens co-convenors seemed more angry with the SNP than the Tory party are.

One of these is understood to be a "solid commitment" on advancing her Referendum Bill, which would seek to set the groundwork for devolved powers to hold a second vote on independence.

It has thus far stalled because of a lack of support from other MSPs.

Ms Regan earlier this week raised a motion of no confidence in Patrick Harvie, which is understood to have had no backers.

Speaking to LBC she 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.”