The SNP needs  a major reset if it is to avoid getting “horsed” in the 2026 Holyrood elections, a former MP has said.

Stewart McDonald, who was ousted as the MP for Glasgow South as a resurgent Scottish Labour won seats across much of Scotland in last week’s general election, said while he trusted John Swinney to “try to turn things round”, the SNP leader would need to be a “ruthless bastard” to succeed in this.

With the election seeing the SNP return just nine MPs, down from 48 in 2019, Mr McDonald added that voters had effectively put a “hard pause” on the party’s independence agenda.

The former MP declared: “The hard pause is here, and we need to think about what we do with that time.”

The former Glasgow South MP was joined by former deputy Westminster leader Mhairi Black, who wrote in a newspaper that the “biggest factor in the loss of support for the SNP was the SNP themselves”.

Mr McDonald, who served as SNP’s Westminster defence spokesperson during his nine years in the Commons, refused to rule himself out of running for Holyrood in the next Scottish elections in May 2026.

But speaking on The Ponsonby and Massie Podcast, hosted by journalists Bernard Ponsonby and Alex Massie, he said while he was “not ruling it out”, he was “not actively thinking about it either”.

Asked directly however if the SNP getting “horsed” was now the most likely outcome of that election, Mr McDonald said: “Yes.”

His comments came as he spoke out about what he described as a “cultural problem” in his party.

Mr McDonald said: “I think we have a cultural problem within the SNP and that cultural problem is about seriousness.”

Former MP Stewart McDonald said he trusted SNP leader and Scottish First Minister John Swinney to ‘try to turn things round’ (Michael Boyd/PA)

While he stressed no individual or policy in the SNP was to blame for the party’s defeat in the general election, the former MP said: “I think we have a cultural problem within the SNP and that cultural problem is about seriousness.”

He cited examples of this as being the de facto referendum policy, introduced by former Scottish first minister Nicola Sturgeon which set out how the SNP would fight the election as a “de facto” referendum on independence, in the wake of the refusal of successive prime ministers to permit a second vote on Scotland’s place in the UK.

Mr McDonald also criticised the SNP’s insistence on having a policy of removing Trident nuclear weapons from an independent Scotland within two years, when he as the then defence spokesperson “didn’t think it was possible”.

He said: “This is what needs to go, this is what needs to be a part of our history.

“And if we are to be successful, if we are to not get horsed in 2026 and enjoy a long spell in opposition, this kind of culture cannot last.”

Speaking about the “wholesale change and upgrade and personality change that the party needs”, Mr McDonald said: “I want to see us grow up, I want to see us get serious. I want to see us have a debate where there are no sacred cows, nothing is off the table.

“There’s a big psychological, political and cultural reset needed within the party.”

However, he noted that the SNP conference next month has a debate scheduled on what the national anthem for an independent Scotland should be – something he insisted he could not “give a monkey’s” about.

Mr McDonald said he believed Mr Swinney – who only became SNP leader in May this year – could deliver the change required.

He said: “I do trust John Swinney to try to turn things round. I think he could do it. I think he wants to do it.

“But it will require him, if I can use some fruity language, to be a ruthless bastard.”

He added: “I told him if you get the calls right, and you have the right kind of agenda, and you need to be a bit of a bastard, people like me will have your back.”

Also on Saturday, Ms Black wrote in the National, criticising the SNP organisation and claiming there had not been enough investment or improvement during the party’s political domination of Scotland.

The former deputy Westminster leader – who stood down at last week’s election – went on to say “internal cracks” within the party had become “chasms”.

“Renewed and festering resentment towards the SNP hierarchy has fuelled so many of the party’s own goals in recent years,” she said.

“As has the increasingly public political tug-of-war between the progressive left and the socially conservative right.

“The problem at the heart of the SNP is that independence is pretty much the only thing all members agree on.

“Being seen to spend more energy fighting amongst ourselves than we spend helping people out of poverty, being seen to care more about the process of independence than we do about convincing people as to why we should be independent, is exactly why the SNP seem out of touch to so many.

“Until the SNP agree on how progressive they want to be, I fear the party’s self-destruction has further to go yet.”