Humza Yousaf has said the SNP should take its defeat in the Rutherglen and Hamilton by-election “on the chin” as voters sent a message to the party.

Katy Loudon lost in a 20.4 percentage point swing to Labour’s Michael Shanks in the South Lanarkshire seat, pulling in less than half of the votes of the winner.

The result has led some analysts to suggest Labour could return to being the biggest party north of the border at the next general election if the result is replicated.

Speaking to the PA news agency on Friday in Dundee, the First Minister said: “It’s a tough day for the SNP, a disappointing result, there’s no point pretending otherwise.”

He said “a number of factors” were at play, including the “reckless actions” of former SNP MP Margaret Ferrier, whose breaking of Covid regulations led to her being kicked out of the party and a recall petition which sparked the by-election.

He added that the “collapse” of the Tory vote – with the party losing its deposit – and the subsequent shift to Labour, and the ongoing police investigation into the SNP’s finances also had an impact.

But he added: “The SNP has to really take the result on the chin as well and understand there’s a message that voters are sending to us too.

“We will reflect, regroup and we’ll reorganise, and come back stronger.”

SNP Westminster leader Stephen Flynn told BBC Radio Scotland on Friday morning that it cannot be “business as usual” within the party following the result.

Asked about Mr Flynn’s comments, the First Minister said: “It’s been obviously less than 12 hours since we got the result of the by-election.

“There’ll be reflection that has to happen and has to happen with pace, so we’ll do that.

“I think we need to make sure the party is a nimble and effective campaigning machine, and I think that’s where the SNP is at its strongest.

“We also have to make sure our message is really crisp, really clear to people.”

The party should utilise its “good track record” in Government, the First Minister said, as well as highlight Scottish independence as being “key” to alleviating “some of the suffering of things like the Westminster cost-of-living crisis”.

Asked if he bears any personal responsibility for the by-election defeat, Mr Yousaf said he has to “reflect”, adding it “falls to me” to make sure the party is “ready and fit” for fighting a general election.