Humza Yousaf has cancelled a planned speech as he battles for political survival, with SNP Westminster leader Stephen Flynn saying the First Minister will “come out fighting”.

Mr Yousaf was due to speak about the labour strategy in an independent Scotland at Strathclyde University on Friday.

But a source close to the First Minister confirmed the event has been cancelled.

It comes as the Alba Party MSP whose vote could be crucial to Mr Yousaf’s future has written to the First Minister, setting out demands in exchange for her support in a vote of no confidence in him.

Ash Regan, a former SNP minister who defected to Alex Salmond’s party, said she wants to see progress on Scottish independence and defending “the rights of women and children”.

Meanwhile, Scottish Labour sought to put further pressure on the SNP by lodging a no confidence motion in the entire Scottish Government, rather than just Mr Yousaf.

If passed, this could lead to a Scottish Parliament election.

Labour leader Anas Sarwar said: “It’s a matter now of when – not if – Humza Yousaf will step down as First Minister.

“It would be untenable for the SNP to assume it can impose another unelected first ninister on Scotland.”

Mr Yousaf is battling to save his position as First Minister after his former allies in the Scottish Greens vowed to vote against him in a motion of no confidence.

That came after the SNP leader dramatically brought the powersharing deal with the Greens to an end on Thursday, and he now faces a backlash which could cost him his job.

A tight vote is expected at Holyrood next week, and since the SNP have 63 out of the 128 MSPs, Ms Regan’s vote would appear to be crucial in getting Mr Yousaf over the line.

Mr Flynn told BBC Radio Scotland’s Good Morning Scotland programme on Friday: “Humza Yousaf is a man of profound integrity. I had a conversation with Humza last night.

“He was reflective, but he was also very clear to me that he’s going to come out fighting because he believes in what he says.

“He believes in delivering for the people for Scotland. He believes in creating jobs and opportunities for the next generation.”

Asked if Mr Yousaf would be speaking to the Greens ahead of the vote, Mr Flynn said: “I would anticipate so, just as I would anticipate there would be conversations with others as well.”

Mr Flynn also said he expects Mr Yousaf to win the confidence vote and continue as party leader and First Minister.

Speaking to Radio 4 later, Mr Flynn suggested he would not stand to be SNP leader if Mr Yousaf were to resign.

Ms Regan, a former Scottish Government minister, posted a copy of her letter to Mr Yousaf on social media.

It said: “Independence for Scotland, protecting the dignity, safety and rights of women and children, and providing a competent government for our people and businesses across Scotland remain my priorities.

“My door is open to discussing the progress of my proposed Scottish Parliament Powers Referendum Bill.”

Ms Regan’s Bill would seek a referendum to ask the Scottish public if Holyrood should have the powers to negotiate and legislate for Scottish independence.

On Thursday night, a source close to Mr Yousaf said he was “absolutely not” considering his position following the chaotic events earlier in the day.

His decision to end the Bute House Agreement with the Scottish Greens was branded an act of “political cowardice” by the smaller pro-independence party.

The Greens will back a no-confidence motion proposed by Scottish Conservative leader Douglas Ross, leaving Mr Yousaf facing a knife-edge vote.

Lorna Slater, co-leader of the Greens, told the PA news agency on Thursday: “We no longer have confidence in a progressive government in Scotland doing the right thing for climate and nature.”

On Friday, she told the BBC her MSPs could hold another meeting to discuss the matter, but so far they have not been approached by the SNP.

The Bute House Agreement gave the SNP-led Government a majority at Holyrood but it came under strain in recent days after the Greens said they would put the future of the deal to a vote by their members.

Some in the Greens were unhappy after the Government dropped a 2030 climate target, and over the decision to pause the prescription of new puberty blockers at Scotland’s only gender clinic for young people.

With the Greens voting in favour of the no-confidence motion, there would be 64 out of 128 MSPs who do not back the First Minister.

Alba leader Mr Salmond said Ms Regan is now the “most powerful MSP in the Scottish Parliament”.

Presiding Officer Alison Johnstone can cast tie-breaking votes but would be expected to vote in favour of the status quo.

Any vote is likely to take place next week, with timings to be confirmed by parliamentary authorities.

The SNP leader has accused the Tories of game-playing, insisting the powersharing deal with the Greens had “served its purpose” and lasted 19 times longer than Liz Truss’s premiership.