HUMZA Yousaf is set for a “thumping” in his first big electoral test since taking over as SNP leader, party insiders believe.

The First Minister faces a collapse in SNP support in the Rutherglen & Hamilton West byelection, which is expected to be confirmed next week. 

The SNP has lost only one other parliamentary byelection in its 89-year history.

Activists report “embarrassment” at being asked to promote the party on the doorstep given its financial problems, including a police probe, and lack of progress on independence.

One councillor admitted they could not “in good conscience” ask people to vote for the SNP at the present time.

Labour sources also report the SNP vote is “very soft” with an unusually high proportion of former SNP voters now describing themselves as don’t knows - an ominous sign for the Nationalists.

Mr Yousaf’s party is defending a majority of 5,230 in the seat, which was won at the 2019 general election by Margaret Ferrier.

She lost the SNP whip in 2020 after travelling from London and Scotland by train despite testing positive for Covid. 

She was sentenced to 270 hours of community service last September after pleading guilty to having culpably and recklessly exposed the public to the virus.

She was also suspended from the Commons for 30 days last month for the breach of Covid rules, triggering Scotland’s first recall petition.

If 10% of the registered electors in her seat - or 8,113 out of 81,124 people - sign the petition in person, it triggers a byelection in which Ms Ferrier could also stand.

The 62-year-old, who now sits as an independent MP, has said she deeply regrets her action, but refused to quit to create a byelection directly.

South Lanarkshire Council started the recall process on June 20 and it ends tomorrow at 5pm.

The signatures are due to be counted and verified on Tuesday, with the result known by the evening. 

With all the main parties, including the SNP, supporting a byelection, the petition is widely expected to meet the threshold for a new vote.

If confirmed, Labour would launch its campaign on Wednesday.

The SNP plans to move the writ for the byelection as soon as Westminster returns from summer recess in September, meaning a belection in early October. 

Labour has selected teacher Michael Shanks as its candidate, while the SNP have chosen local councillor Katy Loudon, who previously praised Ms Ferrier as “the best”.

The seat has changed hands several times in recent years, with Ms Ferrier winning it from Labour in 2015, then Labour regaining it in 2017 before Ms Ferrier won it back in 2019.

The SNP’s share of the vote at the last general election was 44.2% to Labour’s 34.5%.

An SNP source estimated the party would be lucky to get 25% in a byelection.

“It’s a goner,” they said. “It’ll be a total thumping. Folk are embarrassed to go out and push for the party. Katy Loudon is a good person but she’s not a unifying candidate.”

SNP MSP John Mason, who won the Glasgow East Westminster byelection in 2008 and whose Shettleston seat is next to Rutherglen & Hamilton West, said it was too early to predict the result, but admitted it would be tough for the SNP to hold it.

He said: “I think it’s going to be a challenge for the SNP but I’ll certainly be going over and campaigning if it goes ahead. 

“I think if Labour don’t win it, I think it will be quite embarrassing for them.”

He went on: “The SNP has had a few challenges recently. You can’t go on forever being the party of government and winning every single election.

“When you’re older and you’ve been involved in this longer, you’re maybe a little bit more relaxed about it. But every party is going to have ups and down along the way.

“Labour used to control everything in Glasgow and Scotland and that eventually came to an end. So the SNP’s not going to ride high forever and ever.

“I certainly hope that we’ll hold this byelection and I’ll certainly be out there campaigning and I’m sure a lot of other people will as well, but ultimately it’s in the hands of the voters.”

The only other parliamentary byelection lost by the SNP was Dunfermline in 2013 after MSP Bill Walker was convicted of assault, with Labour’s Cara Hilton gaining it.

Besides tarnishing Mr Yousaf’s reputation, a loss for the SNP in Rutherglen & Hamilton West could also put a dent in his party’s bank balance. 

The last time the SNP fought a byelection it spent £98,958 out of the £100,000 legal limit, yet failed to gain Shetland from the Liberal Democrats, who spent £64,534.

Although Westminster has had a recall system since 2015, there is no Holyrood equivalent, allowing disgraced MSPs to keep claiming their salary.

Former SNP finance secretary Derek Mackay took a wage for more than a year after quitting for pestering a 16-year-old boy with texts despite being absent from Holyrood.

Scottish LibDem MSP Willie Rennie said the Scottish Parliament must catch up.

“Scandal-bound MSPs can sit on the backbenches claiming a full salary for years until the next election comes around without the voters having a say. 

“The Scottish Parliament should have serious sanctions for people who behave inappropriately and a route map for how to sack MSPs in cases of proven misconduct.   

“We cannot be the only workplace in the country where there are no rules.

“There must be consequences for politicians and the decision about whether someone is fit for post should ultimately rest with the people who put them there.” 

An SNP spokesperson said: “Should, as we expect it will, the recall petition meet the threshold, the SNP will move the writ within the first week back after summer recess. 

"The SNP look forward to campaigning to elect Councillor Katy Loudon, who will stand up for the constituency of Rutherglen and Hamilton West at every possible opportunity."