The SNP leadership contest has descended into a “squabble”, Sir Keir Starmer said after two candidates raised concerns about election integrity.

The leadership campaigns of Kate Forbes and Ash Regan have called for independent auditors to oversee the process, while the third candidate, Humza Yousaf, dismissed their calls as “baseless smears”.

Labour leader Sir Keir was asked about the contest to replace First Minister Nicola Sturgeon as he visited the biotech company Roslin CT in Edinburgh on Thursday.

He said: “This is a very important election, therefore transparency and integrity and accountability are hugely important.

“For families across Scotland that are struggling with the cost-of-living crisis, to see the SNP descend into this squabble, talking and arguing with themselves – not about the budget or the cost of living but about how bad their record has been in Government – I think most people with think what on Earth are you doing?

“You’ve clearly run out of road, run out of ideas.

“It’s for the Labour Party to make the positive case for a better Scotland within a better United Kingdom.

“I’m humble about this, I recognise that there’s no reason why those voters who may be disaffected with the SNP necessarily transfer to another party.

“It’s for us to earn those votes.”

Sir Keir was also asked whether Scotland should have a separate arrangement with the EU, in light of the Windsor Framework which provides a new deal for Northern Ireland.

The SNP has attacked Labour as a “pro-Brexit party” which would not undo the damage nationalists say has been caused by leaving the EU.

Sir Keir said: “I don’t think there’s a technical case or any case for Scotland having a separate set of arrangements.

“If you look at Northern Ireland, the problem for Northern Ireland was that it didn’t have the same arrangements as the rest of the United Kingdom.

“I don’t think it makes sense to replicate that problem and insert it into Scotland.

“What we want is a better arrangement for the whole United Kingdom.”

Meanwhile, reacting to news that TikTok is being banned from UK Government phones, Sir Keir said he agrees with the move and said the Government was “behind the curve” as other countries and Parliament had already brought in bans.

Discussing the Budget, he said there should have been a “tailor-made” approach for doctors’ pensions, rather than a tax cut which would benefit the richest in society.