SNP leadership hopeful Alison Thewliss has named Cumbernauld, Kilsyth and Kirkintilloch East MP Stuart McDonald as her pick for deputy. 

The joint ticket will be a blow to rival Stephen Flynn as both men were part of the so-called Tuesday Club faction within the parliamentary group. 

Initially set up as a regular five-a-side night it quickly became a thorn in the side of Ian Blackford and played a critical role in his downfall. 

One ally of Ms Thewliss said Mr McDonald’s loyalty was to the party. “He's not in factions, wings and all the rest of it,” they said

They added that while the Cumbernauld, Kilsyth and Kirkintilloch East MP had been “in” the Tuesday Club, he was not “of” the Tuesday Club. 

“I think he is just there for the football and the pint. He's definitely not part of an internal power struggle.”

According to reports - though yet to be confirmed - Mr Flynn has picked Mhairi Black as his running mate. 

One of his backers told the Times that they were concerned by Mr McDonald breaking for Ms Thewliss. “I think he’s been lazy about it and thought he had it in the bag,” said one backer.

MPs will vote for the new leader tomorrow evening at the group’s annual general meeting following a “valedictory” speech from Mr Blackford.

He announced his resignation on Thursday morning. It was widely predicted that Mr Flynn would run for the post unopposed, but Ms Thewliss unexpectedly threw her hat into the ring on Saturday night.

Mr McDonald said he was “humbled” to be asked to be Ms Thewliss’s deputy.

“The party is at such an important point in its history,” he tweeted. “Our mission is to actively build and make the case for a progressive alternative to Tory austerity and Brexit: Scotland's independence in Europe. 

“As deputy leader of the group, I'll work with Alison, to build a strong focused Westminster team that works in collaboration with colleagues, right across the party. We've got a big job ahead. Let's get it done.”

A source on Ms Thewliss’s campaign team described Mr McDonald as a “clear thinker, an absolute workhorse.”

“He’s a grafter, not at all a showman,” they added. 

They said the deputy role was “really about managing the kind of background group machinery in a sense.”

“It's not at all a flashy role, but it is highly important and needs somebody who's going to put the hours in to take care of the mechanics, things like managing group resources, dealing with staffing issues as they arise, inevitable kind of political tensions that come up from time to time, relations with the wider party. 

“What you need in a deputy leader to be blunt is somebody who's going to be the first person in in the morning, and the last person to leave at night.” 

They added that the position was quite critical to dealing with complaints from staff.

One of the factors that ultimately led to Mr Blackford standing down from the leader's job was the criticism over his handling of a complaint made against former chief whip Patrick Grady.