The very idea of screen legend Brian Cox’s move into television comedy with a new BBC sitcom is without doubt a cause for celebration.

But it has certainly caused the nation’s collective eyebrows to raise.

The classical actor has long stunned the theatre world with the likes of his King Lear, taken cinema audiences aback by stealing the limelight from Brad Pitt in Troy or scared us senseless with the sheer menace of his original Hannibal Lecter.

Yet, now the Hollywood A-lister has committed not only to sitcom - he’s the star of Bob Servant Independent, the story of a larger-than life Dundonian eccentric – but he’s appearing on a relatively low-profile TV platform and the show is filmed in Dundee.

In terms of career surprise moves, it’s right up there with Sir Ian McKellen turning up in the Rovers Return and ordering up a plate of Betty’s hotpot.

“I’ve been away, living in New York and I guess making this comedy show is about me realising it’s time to come home,”  Dundee-born Cox explains while relaxing at the BBC Scotland HQ at Pacific Quay. “But it’s also about returning to the light.”

The light? Cox is speaking literally and figuratively. Broughty Ferry, he explains, has great light. And he rewinds on summers as a boy waking at 4am to welcome the sunshine. But the figurative light he’s moving towards is a direct reference to the darkness of his past, the time spent by his ancestors in Glasgow.

At 66, and clearly cognisant of his own mortality, Cox wants to move away from the pitch black memories.

“My family are Irish - my grandfather came from Derry, and then came to Glasgow,” he reveals. “And when I look at my family history the hardest time of their lives was when they all lived in the city. They were miserable, mad, and they all lost children.

“My great-grandfather on my mother’s side died in an asylum in Gartcosh in the most appalling circumstances. And he lost five of his eight children. My grandfather lost his wife, his mother and five siblings, having watched his father being consigned to the poor houses, with his younger brother going into a reformatory and the other brother go into care. So in my DNA there are very bad memories.”

Brian Cox ‘loves the people of Glasgow’ and is ‘joyous about what they’ve survived’. But he believes Glasgow has demanded a great deal from its inhabitants; economic repression, the religious divide and Catholic discrimination, and the vast gap between rich and poor.

“My great-grandfather’s mother in law lived on a stair - literally - in Cowcaddens,” he reveals. “Yet, at the same time, Glasgow was a city of great wealth and built on slavery.” He adds, in soft voice; “Look, I have respect for the city. The Glasgow Arts School is the greatest art school in the world. But we (his family) had to visit Glasgow in the fifties and it scared the bejaysus out of me. The city glowers. You only have to look around the city to see the homes of the tobacco merchants who bought and sold people. Did you know families in Ayrshire had black slaves who were made to serve their masters wearing little kilts?

“And did you know that in Glasgow in the 1950s, neighbours were deliberately split up in a form of social engineering to recreate communities? Of course, town planners claimed to have positive  reasons for doing this, but can you imagine what this did at a human level?”

The socialist actor’s critical appraisal of Glasgow (he supports independence, but not the SNP) isn’t directed against its ordinary people.

“Look at Billy (Connolly),” he says. “He’s amazing. And I love his comedy but his storytelling comes from the darkness of the city he was born in. It’s the comedy of oppression. I’d be a completely different creature had I been brought up here.”

He adds, with a wry smile; “That’s why my sitcom character Bob Servant (a hamburger seller-turned politician) has to come from Dundee. He’s buoyed by the East Coast light off optimism. His comedy is upbeat, not like the miserable Glaswegians we see in sitcoms such as Rab C. Nesbitt. Now, I have to say Nesbitt is a very, very funny show. But it’s a different funny. Like Billy’s comedy it also comes out of the darkness.”

Glasgow’s weather, the almost ever-present clouds cover us in a blanket of melancholia, says Brian Cox. And it’s hard to remain upbeat with greyness bearing down. 

“It makes a vast difference to the demeanour. You can see how it formed people such as the actor Phil McCall. Phil was a terrific actor, but he suffered from SAD and hung himself. And you can understand why so many people leave. It wasn’t a surprise to me that Billy came back to live in Scotland but to the North East. Where the light is!”

Brian Cox’s thoughts on his family’s traumatic lives has been polarised, thanks to a recent investigation of his family tree. And it’s clear he wants to gain from the knowledge, to seek out the light, in whichever form that takes. And one form is laughter. He admits he  has long worshipped at the altar of the comedy greats.

“Absolutely,” he says, smiling. “I love comedy, I was a Jerry Lewis/Dean Martin fan as a kid, And as I’ve gotten older I’ve been looking for more light relief. My favourite show on television is actually The Big Bang Theory (C4). I think it’s brilliant. But until now I’ve never really performed it, even though I’ve always felt I had a natural comic bent.”

He adds, grinning; “Having said that, in the past I’ve actually tried to bring comedy to my serious roles, even in my King Lear (a tale of madness and betrayal), because I look for the absurdity in life rather than the drama mask.”

Cox wanted to become an actor ever since he performed Al Jolson impersonations aged three on top of the bunker.

“My dad loved me doing this, and I loved the applause,” he recalls. “Right from that first moment I knew this was what I wanted to do. Now, I get to act. And I get to appear in comedy. And I love it.”

The actor is set to begin filming a new movie in which he stars as J. Edgar Hoover. Will playing the cross-dressing FBI boss allow for incorporation of comedy into the role? “Yes, there are opportunities with this,” he says, grinning.

Brian Cox clearly loves comedy, but can he take a joke when aimed in his direction? Here goes. You suggest perhaps he’s been a little harsh on Glasgow? It can’t all be down to DNA and ancestry. Was he once dumped by a Glasgow girl?

“Not at all,” he says with a booming laugh. “I was once dumped unceremoniously by a girl from Pitlochrie, but no. Not Glasgow. And while I’ve always loved the Glasgow humour, the city is just not for me.”

He can’t resist a final pay-off. “Did you know it was a Dundonian, Will Fyffe who wrote I Belong To Glasgow?  You see, only a Dundonian could take Glasgow and all it’s darkness and write such an upbeat song about it.”

* Bob Servant Independent, Wednesday 23 January, BBC4, and BBC2 Scotland at 10pm,