YOU WONDER how much remains of the natural rebel in Cathy Tyson.

As the actress takes a coffee break from rehearsals for her latest theatre production Rebus: Long Shadows, you search for a glimmer of the 13 year-old who 40 years ago ran off to London to work as a chambermaid, only to be hauled back by police.

You look for a hint of the defiant star, ears still ringing from the applause she enjoyed from starring alongside Bob Hoskins in (now cult) 1998 Britpic Mona Lisa - who then threw a deaf ear in the direction of Hollywood when the casting calls came in.

And you wonder if the boldness of the performer, who featured in major dramas such as Band of Gold - yet walked away from the job to become an English and Drama student and live in digs, aged 43, still pervades.

Right now, Tyson is in Glasgow, starring as DI Siobhan Clarke in Ian Rankin’s new Rebus adventure, adapted by Rona Munro, which sees the now retired detective (played by Ron Donachie) haunted by the ghosts of crimes past and the spectre of present day - in the form of gangster Big Ger Cafferty (John Stahl).

Clarke is a by-the -book character, the foil to the more pragmatic, old-school cop that is Rebus.

“I’ve really enjoyed researching what it’s like to be a team player, speaking to a detective to gain understanding.”

While Tyson is most certainly bold and defiant, conversation also reveals a real fragility, which stems from a sometimes tortuous experience growing up in Liverpool.

Her dad, a Trinidadian barrister, left her Irish social worker when Cathy was a little girl. The schoolgirl suffered racism from both sides.

“My mum was called an ‘N-lover,’ she recalls with a shudder in her voice. “ I was called an ‘N’ at school. But even after he left us, my mum had a picture of my dad in his wig and gown on the mantelpiece so at least when other kids called me the ‘N’ word, I could say ‘Well, my dad’s a barrister and yours isn’t.’”

The teenage Cathy felt far less than beautiful. The good-looking young boys around were inaccessible, she says, “because I didn’t look like a Sindy doll. I never felt beautiful until I went to Europe.”

Alienated, hurt and with a screaming inferiority complex, the often truanting teenager changed her name to Stacey Smith and ran off to London with a friend. “Thank god a policeman found me. My friend and I were almost abused.”

Back home, Tyson took her early experiences of watching theatre and joined youth theatre in her hometown. She loved the world so much she dropped out of college at 17 and e landed a Youth Opportunities job with the Everyman Theatre, home to the likes of the McGann brothers and Willy Russell.

“It got me out of trouble,” she says of the theatre world. I was a very cheeky schoolgirl but I started to find my voice in drama.”

Tyson, a truly precocious talent, joined the Royal Shakespeare Company in 1984. She once said; “Liverpool gave me a mouth. But Shakespeare gave me a voice.”

Two years later, director Neil Jordan picked the actress to play the elegant prostitute Simone in Mona Lisa. Tyson was a storming success. But if life experience had helped the actress access the widest emotions, it didn’t mean she was confident at all. Tyson turned down Hollywood’s overtures in part because she suffered Imposter Syndrome. “ I’d never gone to drama school,” she reflects. Meanwhile, she had married actor Craig Charles, whom she had met back in Everyman days (they went through “stormy times” when they split but are pals now) and pregnant with their son, Jack.

“And, this sounds terrible, but my mum was a real socialist - she’d play the Red Army Choir records at home - and she saw America as a place not to go to. But I was young. I hadn’t lived. “

Tyson has gone through long periods of self-examination. “It’s about a balance in life,” she says, smiling.

“I just wish I’d gone to therapy when I was younger. Not wait until I was 36. But back then ‘therapy’ was another word for failure.”

Evan after therapy she walked away from acting to go to university. “I had been a bit scared of actors all my working life. And there was always a nagging thought in my mind I needed to learn more. Plus, I was jaded. And I felt I had to step back from myself to find out where I should go in life. I thought I may go into teaching.”

Tyson has continued to break ground in the industry, almost single-handedly breaking down the wall of colour casting. She’s played the lead in Educating Rita, she’s been Eliza Dolittle and Portia and even Lady Bracknell.

Is race less of an issue now in the industry? “Well, I’ve been long aware that I’ve played a black prostitute twice,” she says of Mona Lisa and Band of Gold. “I never used to watch The Bill because black people were all too often cast as criminals. But we have made great progress - and I’m also aware of the opportunities given to me by white people.”

Tyson is thinking of writing her autobiography. She should. She’s thoughtful, articulate. Very smart. And she’s arrived at a good place from which to reflect.

“My regret is that my mum died 10 years ago and I wish she’d seen some of the happier times. As for my dad, I’m just back from Trinidad and I’ve been asking questions about him. I’m building clarity, helping to put the fantasy relationship I had in my head in it’s place.”

Just as importantly, Tyson appreciates here own talent.

“I used to think if I director said I was good they were just being kind,” she says in soft voice, smiling.

“Now, I can at least trust their judgement.”

Rebus: Long Shadows, the Theatre Royal, Glasgow, January 29 - February 2,