Humza Yousaf has dismissed Alex Salmond’s “fantasy” demand for a pro-independence electoral pact as the price for Alba backing the beleaguered First Minister.

The rejection of the ultimatum could prove fatal to the SNP leader’s chances of surviving this week's confidence votes.

His leadership has been in turmoil ever since the shock termination of the powersharing deal between the SNP and Scottish Greens on Thursday.

READ MORE: Humza Yousaf defiant as future hangs in the balance

There are two motions of no confidence to be voted on by MSPs.

The first, tabled by the Scottish Conservatives, is on Mr Yousaf as First Minister, and the second, tabled by Scottish Labour, is on the Scottish Government.

While losing the first would be politically difficult for the First Minister, losing the second would - as per the Scotland Act - require Mr Yousaf and all of his ministers to resign.

Both confidence votes only require a simple majority.

The SNP has 63 MSPs. However, the opposition parties have a combined total of 64.

All parties bar Alba have so far said they will back Douglas Ross’s motion on Mr Yousaf’s record.

So far only the Tories and Lib Dems have confirmed they will support Scottish Labour’s bid to oust the First Minister.

Alba and the Greens expressed some scepticism - though neither have explicitly ruled out voting for the measure.

Mr Salmond's offer was never likely to be palatable to Mr Yousaf and the SNP. One senior source described it as a "delusional."

The former first minister told the Sunday Times that he wanted to see the SNP back his “Scotland United” plan.

He told the paper: “If you remember the Scotland United idea from last year which Humza just ignored, which was very popular with the Yes groups and amongst SNP supporters,” said Salmond.

“It would be difficult to revive it in full now because obviously candidates have been selected [for the general election], but it could be revived in part, or there could be an understanding for the Scottish elections in two years time.

“So a discussion along these lines, so it’s a menu of independence options.”

He added: “We are asking to put independence back as the top priority of the government, which clearly it isn’t now.”

READ MORE: SNP's Kate Forbes hopes Scottish Greens will 'embrace' her

Currently, the SNP holds 61 of Scotland’s 73 Holyrood constituencies.

The only seat held by Alba is Ash Regan’s Edinburgh Eastern, which she initially won for the SNP before defecting. 

Labour’s Monica Lennon tweeted: “Wonder if any SNP MSPs will volunteer to step aside to help seal this deal?”

Asked about the offer, a spokesperson for the First Minister told the Sun: "This is fantasy. There is no possibility of the First Minister agreeing any deal like this with Alex Salmond."

On Friday night, Mr Yousaf wrote to the leaders of the other Holyrood political parties to seek “common ground”.

He hopes to hold separate meetings with each group at Bute House in Edinburgh to discuss how they can “contribute constructively.”

Mr Ross, the Scottish Tory leader, described it as a "humiliating and embarrassing letter, in which Humza Yousaf is begging to be allowed to keep his job."

“His belated abandonment of the Bute House Agreement with the toxic Greens – which he was backing just two days before he finally decided to pull the plug – does nothing to undo the immense damage it has caused.”

READ MORE: Humza Yousaf faces a crisis – of his own making, says Brian Taylor

The Scottish Greens said they would respond formally to the First Minister in due course, but otherwise their position is unchanged.

Scottish Green co-leader Patrick Harvie has said it is “pretty clear” Mr Yousaf will not be able to unite Holyrood.

Speaking on Friday, Scottish Labour’s Anas Sarwar said: “I am more than happy to engage with people of all parties, but it is clear that Humza Yousaf is out of time.”