Supporters of Alison Thewliss believe she could have the numbers to beat Stephen Flynn in the race to replace Ian Blackford as the SNP's Westminster leader.

An ally of Ms Thewliss told The Herald that momentum was now with the Glasgow Central MP and that tomorrow’s vote would now be a “proper contest.”

Ms Thewliss announced a shock bid for the job on Saturday night, saying she had "no intention" of running but felt she had a "duty to step up.

READ MORE: Alison Thewliss in bid to become SNP Westminster group leader

Her candidacy means there will be no coronation for Mr Flynn. The Aberdeen South MP had been expected to stand uncontested at the SNP Westminster group’s AGM tomorrow.

Reports yesterday suggested that Mr Blackford ultimately announced his intention to stand down after realising that his young challenger had the backing of 23 of the party’s 44 MPs. 

However, Mr Flynn's campaign managed to alienate some colleagues at the end of last week when they briefed that one of his first acts as leader would be to sack just about everyone on the front bench.

READ MORE: All eyes on Westminster as Ian Blackford leaves the stage

Ms Thewliss was, her allies said, a “team player” who was "universally popular in the group."

One of the key dividing lines between the two candidates will be over the Westminster group’s relationship with the party leadership in Holyrood.

Some have suggested that Mr Blackford was ousted partly because he was too close and too loyal to the First Minister.

Yesterday, he told the Sunday Mail that he believed he had lost support from MPs because there were "some people in the group that would have preferred me to be a bit more independent."

Ms Thewliss is close to Nicola Sturgeon. Their constituencies significantly overlap. 

One MP who is backing Ms Thewliss said that she “always fights for the jersey, she's SNP to her fingertips.”

They added: “She wants more collaboration with Holyrood, not less, more collaboration with headquarters, not less and more collaboration with party members and party activists, not less.

“She's not interested in building an alternative power base down here in London or anything like that.

“We are the SNP at Westminster. So therefore we need to operate, look like, sound like what like we are part of the same party”

Our source said the SNP group needed a “bit of refocusing” following last month’s Supreme Court verdict.

“We should always be willing to challenge ourselves and make changes to our strategy when we need to. The group has a lot of views on what that should be. 

"Alison's enthusiastic about engaging with the group on how do we make sure we're kind of sparky and relevant and making our case in a way that is cogent, understood and connects with people."

READ MORE: Clear-out of SNP's old guard has been a long time coming

“We've obviously not had, I think it's fair to say, the best couple of days since Ian stood down," they added.

"She wants to offer a way forward that draws a line under that and allows everybody to buy back into what we're all here to do, which is make the case for independence as an alternative that the public can buy into.”

The Herald:

Mr Flynn declared his candidacy late last night. 

"Few working class folk ever make it to Parliament, fewer still run to be political leaders," he tweeted. 

"Even fewer do so having spent almost the entirety of their teenage and adult years battling a physical disability.

"Your experiences tend to shape you and I'm no different."

He said the answers to "to the problems we face don't lie in Westminster."

"Strong voices are needed and I'm ready to stand up for Scotland." 

His supporters include what's known as the Tuesday Club, a group of MPs including David Linden, Gavin Newlands, Alan Brown, Stuart MacDonald and Mr Flynn, who meet up for a curry and a game of football every week. 

Meanwhile, Kirsten Oswald, the SNP’s deputy Westminster leader, has also announced her intention to stand down tomorrow. She said it was time to “pass the baton to one of my many talented colleagues."