A WOMAN in the street has just given Gary Lewis a sharp cuff round the ear. "That was for the bad thing you did," she chides. The actor, his blue eyes twinkling, looks mock chastised.

"You realise that wasn't me?" he says, breaking into a grin. "That I was playing a character?" The woman purses her lips, her face softening a bit. "I know," she concedes. "What you up to next?"

What indeed. Gary, 58, is seldom idle. Or resting, as acting types call it. He's currently gracing television screens in ITV crime drama The Level, which is halfway through its six-week run.

No stranger to the genre, the Glasgow-born actor is fresh from starring in BBC thriller One of Us alongside Laura Fraser, Kate Dickie and Julie Graham.

In the pipeline is a role in the much-anticipated ITV series, Muncie, which centres on the Lanarkshire murder spree of serial killer Peter Manuel in the 1950s.

First, though, we are here to talk about his latest onscreen incarnation as Gil Devlin in The Level. Gary picks carefully through the synopsis, cautious of revealing any crucial spoilers.

"A lot of the heart and complexity about the drama is to do with family ties," he says. "It is not a straightforward police crime drama – there is a lot more to it."

We are sitting in a quiet room above a coffee shop. Away from the hiss of the espresso machine and clink of cup on saucer, the only sound is Gary's distinctive gravelly voice.

He speaks in the mesmerising rhythm of a true storyteller, the pitch sometimes so low and deep that you have to lean forward to catch the words as they melodically roll off his tongue.

The opening episode of The Level saw Detective Sergeant Nancy Devlin caught between a rock and a hard place when the murder of haulier and drug trafficker Frank Le Saux – Ashes to Ashes star Philip Glenister – unwittingly thrust her into the centre of a major investigation.

Nancy, played by Karla Crome whose past roles have included Misfits and Under the Dome, is hiding the dark secret of what Gary describes as a "dodgy and duplicitous existence". He plays her estranged father Gil, an alcoholic and a former policeman.

"It is a very interesting script because these families are kind of hanging together by a thread. There is so much conflict and bad stuff from the past that hasn't been resolved. The guy that Nancy has this compromising relationship with is a successful businessman in Brighton and her father figure.

"Nancy and her own dad have a lot to sort out. They don't have that close father-daughter relationship. My character basically detests this guy she has a father-like relationship with. All of this information comes across as the drama unfolds and you have to pay attention."

Complex family relations have become something of Gary Lewis trademark. From playing the dutiful son in Orphans to the gruff father in Billy Elliot, he has a talent for being the grit in the oyster.

Past roles include a recovering alcoholic alongside Peter Mullan in My Name Is Joe and the hackle-raising, malevolent racist McGloin in the Martin Scorsese-directed Gangs of New York, each stirring dark and conflicting emotions that linger long after the final credits roll.

Gary will next appear on our screens in the coming months in Muncie, about the detective who doggedly laboured to bring Peter Manuel to justice. Manuel will be played by Martin Compston with Douglas Henshall in the role of William Muncie.

Gary has been cast as William Watt, a man wrongly accused of murdering his wife, daughter and sister-in-law in the Burnside area of Rutherglen in 1956.

Muncie first arrested Manuel in 1946 for housebreaking and a string of violent sexual assaults. Released from prison in 1955, Manuel vowed revenge and embarked on a two-year killing spree, claiming eight lives in close-knit communities across Lanarkshire.

As Muncie attempted to catch the man dubbed "the Beast of Birkenshaw" – named after the area from which the killer hailed – Manuel, in turn, went to great lengths to taunt his pursuer, leaving tantalising clues and even sending birthday cards.

More than half a century later, Peter Manuel is a name which still strikes fear into the heart of many across Scotland.

Gary was a baby when Manuel was hanged on the Barlinnie gallows in 1958, but growing up in Easterhouse he often heard stories about Manuel's reign of terror.

He says his mum Mary had a strong reaction when he told her about his part in the mini-series.

"It brings back so many memories," he says. "My mother worked in MacFarlane Lang biscuit factory and told me there were lassies beside her who were absolutely terrified because they lived in that area. They all knew who it was, this monstrous character, but the police couldn't get him."

There is an eerie feeling of proximity for Gary himself: as the crow flies Birkenshaw is less than a handful of miles from the streets where he played as a youngster.

"My dad got us a telescope and with that we could tell the time on the tower in nearby Bargeddie," he says. "It was just beyond there [in Birkenshaw] that Manuel lived."

It is a stark departure from other recent TV crime dramas that Gary has starred in.

"There is always an issue about drugs: the transportation of drugs, the buying and selling of drugs, the dealing of drugs, the violence and horror around drugs.

"This is pre all that. There is no profit. Manuel was a deeply violent, harmful, psychopathic, disturbed person. He got his kicks from fear and terror."

Gary's projects in recent years include the hit US television series Outlander. 

Sony Pictures Television films the show on location across Scotland with many of the interiors shot at Wardpark Studios in Cumbernauld.

Set on the brink of the 1745 Jacobite rising, the show has become a global phenomenon.

“The fan base is extremely passionate,” he says. “It is strange because I live in Scotland and Outlander isn’t massive here to the extent it is in Australia, America and Canada. There are fans all over the world.”

His character, clan leader Colum MacKenzie, bowed out in dramatic fashion and Gary admits he will miss being part of the show.

“It wasn’t until I was in the car going home that it hit me it was my last day,” he says. “Even when the producers came down for my final scenes, it still didn’t sink in.

“It was only afterwards that I suddenly thought: ‘Jesus, that’s me. I’m done.’ Everyone else still had scenes to shoot and I was already down south working on something else by the time we had the wrap party in Glasgow, so I never got the big cheerio.”

The Level is on STV, Fridays, 9pm. Follow @TheLevelTV on Twitter