SPECULATION has mounted over who will be next to join Alba after sources said a "big hitter" would be announced this evening.

Figures in the Yes movement have wondered whether SNP MP Angus MacNeil will join Alex Salmond's new party next as he has been critical of the SNP’s strategy to achieve independence.

But The Sun was told senior figures have been pondering over the weekend if MacNeil has "bottled it".

He did not respond to inquiries from The National last night.

READ MORE: SNP braced for more defections to Alba, says insider

The Times reported that a "big hitter" will be joining the party but it is unconfirmed whether it is an SNP MP.

It is understood Nicola Sturgeon’s party is expecting more of their elected representations in Westminster to make the switch already made by Kenny MacAskill and Neale Hanvey over the weekend.

One insider told The National more high profile SNP politicians would be announcing a move to the new party in the coming days.

Asked if these would include MPs, the source said: “I would say so, yes.”

However, the source refused to say how many more MPs would be resigning from the SNP and joining the Alba Party, and whether the number would be more than a single further MP.

This morning, it was announced that Glasgow councillor Michelle Ferns has left the SNP for Alba.

READ MORE: Glasgow councillor latest to quit SNP to join Alex Salmond's Alba Party

Salmond revealed on Friday that he would be leading the new Alba Party and standing as a Holyrood candidate on the North East regional list.

The former First Minister also revealed the party would be fielding at least four candidates on all eight regional lists, but not standing in constituency seats. He called for voters to support the SNP in the first past the post seats.

Kenny MacAskill, the MP for East Lothian, revealed on Saturday he had left the SNP and had joined the Alba Party, while Neale Hanvey, the MP for Kirkcaldy and Cowdenbeath, and former SNP MP Corri Wilson announced their defections yesterday. 

MacAskill is standing for the Alba Party on the Lothian list, while Hanvey and Wilson on the Mid Scotland and Fife list and South of Scotland list respectively.

On Friday, Chris McEleny, a councillor in Inverclyde and a prominentadvocate of a Plan B to achieve independence, also announced he had left the SNP and joined the Alba Party. McEleny will stand on the West of Scotland regional list.

Lawyer Eva Comrie will be standing in the Mid Scotland and Fife region. Comrie was previously an SNP candidate for this list.

Businesswoman Cynthia Guthrie, CEO, of the Guthrie Group, will stand in South of Scotland.

It comes as Nicola Sturgeon made a veiled criticism of the Alba Party in her speech to the SNP campaign conference.

WATCH: Nicola Sturgeon appears to have veiled dig at Alex Salmond in SNP speech

The First Minister, in an address broadcast on social media, hit out at those “who treat politics like a game”.

Sturgeon said: “In politics, things that once seemed so desperately important, don’t seem so now.

“I don’t have much time these days for the ‘who’s up, who’s down’ approach to politics. And I definitely have much less patience for those who treat politics like a game and for anyone that indulges self-interest ahead of the country’s best interests."

The SNP leader added: “If the past year has taught us anything, it is that politics is about improving people’s lives, or it is about nothing at all. And that takes purpose and it takes hard work.

“The pandemic has also, for me, reinforced some fundamental principles of leadership. It is important to always treat people like adults, and to lead like a grown-up too. Don’t pretend to be infallible, learn from your mistakes – don’t deny those mistakes.”

Over the weekend, Salmond insisted Sturgeon was the best person to lead Scotland.

He told the Sunday Mail: “I believe that she should be the First Minister because the SNP should win a handsome majority. She is the only viable independence candidate and therefore she is the best one.

“I have no ambition to be in government. I am not standing to be First Minister, I am standing for the Alba Party on the list to build an independence super-majority.”