Richard Leonard always carries two handkerchiefs. “I had to testify to this in a court case,” he tells me, pulling one out after we retreat from the rain into a coffee shop. “A fellow Labour canvasser had the top of his finger bitten off by a dog. One handkerchief was wrapped around the bottom of his finger and one was placed around the top.”

I meet Leonard, 55, the frontrunner to be the next Scottish Labour leader, in Rutherglen, near Glasgow, where he has been door knocking for a council by-election. He is lanky, with floppy grey hair, a navy suit and a red tie, and speaks softly, with a Yorkshire accent. For decades, he has campaigned for Labour, but only became an MSP – for Central Scotland – in 2016 and was little known outside a circle of left-wing activists.

Then, on 29 August, Scottish Labour leader Kezia Dugdale resigned. Like almost everyone in the party, Leonard found out from the news. “I was sitting watching television at home with my wife,” he recalls.

The next day, as high-profile supporters of Jeremy Corbyn (such as 2014 candidate Neil Findlay) ruled themselves out of the race, attention focused on Leonard. But there was a problem. He didn’t even have a Twitter account. “I’ve pointedly abstained,” he says, sipping a cup of tea. His team hastily set up a profile, which he still largely ignores.

The leadership election, the result of which will be announced on 18 November, has become intensely personal. Leonard’s rival candidate, Glasgow MSP Anas Sarwar, was forced to relinquish his shares in his family’s cash-and-carry business after it was revealed not to pay employees the voluntary living wage. Allies of Dugdale, meanwhile, have claimed her resignation was prompted by a “plot” against her.

Minutes before I meet Leonard, I discover that Stephen Low, the aide who set up the interview, has had to stand down after issuing a press release describing the comments as “pish”.

“I don’t want the election to be conducted in an uncomradely way,” Leonard tells me. “If anybody involved in my team steps out of line in a way that I think is unacceptable I will deal with that.”

He continues: “I think I am viewed as somebody with a degree of integrity inside the Labour Party. I’m not prepared to see that sacrificed in my name by anybody associated with the campaign.”

The leadership election has also triggered a debate about backgrounds. Both Sarwar and Leonard were educated at private, fee-paying schools (Leonard won a scholarship). But the latter would also be the first English-born Scottish leader in a country known for backing “anyone but England”.

“I’m afraid I can’t do anything about that; it’s a done deal,” Leonard jokes. He moved to Stirling as a student to study politics and economics, and has spent his working life in the Scottish trade union movement. He downplays anti-English hostility, insisting “people are fairly relaxed about it”.

In the race, Leonard is regarded as the Corbynite candidate. Like the national Labour leader, he has been endorsed by Unite, the party’s largest trade union affiliate; his team includes Simon Fletcher, who masterminded Corbyn’s 2015 leadership victory.

But Leonard bridles at the comparison. “I’m too long in the tooth to be a Corbynista,” he insists. A self-described “Labour loyalist”, whose hero is the party’s founder, Keir Hardie, he has campaigned for candidates of all ideological persuasions.

He does, however, align with Corbyn on Brexit. Although, like Scotland, Leonard voted Remain, he was one of just three Labour MSPs to vote against a Scottish government motion protesting the triggering of Article 50.

“It was a symbolic vote it didn’t have any direct meaning,” says Leonard. Nevertheless, his views contrast sharply with those of former leader Dugdale, who has called for a referendum on the final Brexit deal.

“One thing that’s been wrong in politics is political elites believe they know better than the people,” he says. “The franchise for the UK referendum was the UK – it wasn’t Scotland, Wales or Northern Ireland.”

But Leonard is standing to be Scottish Labour leader. How can he represent the Scottish vote for Remain? “It was the sovereign will of the Scottish people to stay within the UK in 2014. I’m respecting that.”

Opponents of Leonard complain the race is a union stitch-up and warn that Scottish Labour may once again become a “branch office” of Westminster. Leonard himself says that he aims to co-operate with colleagues south of the border. “There have been times in the recent past when there have been deliberate attempts to delineate the Scottish Labour party from Jeremy Corbyn’s party and to manufacture rows.The Scottish Labour Party’s in third place – we don’t have the luxury to do that.”

It’s late afternoon and the coffee shop is emptying. It was in 2011, the year Leonard came to the rescue with his handkerchiefs, that the SNP won a majority in the Scottish parliament, setting in train the events that led to the independence referendum. Young people – the kind who dominate Corbyn’s rallies in England – voted Yes. Can Leonard win them back?

“A whole generation of young people were captured by the message of hope which came with the Yes campaign in 2014,” he says. “Those young people are starting to awaken to a more radical Labour message.That’s a vision of hope, that’s a message of real change. That’s exactly where I think Scottish Labour needs to be.”