THE family of Teesside-born Marlene Sidaway never thought for a moment that acting was something she should do as a career. "They liked watching things that we did at school but tended to say, 'you don't want to do that daft acting'," she recalls.

So she trained as a comptometer operator. "You don't know what that is, do you?," she surmises correctly. "It was an adding and calculating machine. It's obsolete now - but acting is still going on."

With a career spanning over 45 years, Sidaway is making her debut at Harrogate Theatre in Alan Bennett's award-winning Talking Heads but can claim a previous connection with the Yorkshire venue.

She's being directed in A Cream Cracker Under The Settee by artistic director Hannah Chissick in her final production before departing after three years at the theatre. "My agent put me up for the part but I'd worked with Hannah's father Jack. He used to talk about this little girl he had. I think she was about five then," she says.

They appeared in a play by Wally K Daly, who also comes from Teesside. "We worked together at Grangetown Boys' Club and he wrote a play about the club. It was a great play to work on. Mind you, I was a lot younger and playing a blonde," says Sidaway.

She went down to London in the 1960s to join a children's theatre company, then she went into weekly rep and finally studied at E15 drama school. Both her parents are dead now, so she doesn't have as much cause to return to Teesside, although she still has friends there whom she plans to visit during the Harrogate run.

A Cream Cracker Under The Settee is one of three plays being staged in Talking Heads. Chissick is also directing A Chip In The Sugar, while Bed Among The Lentils is directed by Phil Lowe in his main house debut.

Sidaway has previously performed in another Talking Heads monologue, Lady Of Letters at the Stephen Joseph Theatre in Scarborough. "That was lovely," she says. "It's such wonderful stuff to work on and now it's very good to be Doris, although Thora Hird is a hard act to follow."

Hird played Doris in the original TV production. She's an obsessively tidy old lady who's taken a fall. Lying on the floor unable to get up, she has time to reflect on the changing world and whether her fixation for cleaning has gone too far.

"At first glance, you think Alan Bennett has done it all for you," she says. "You think you know the character and the words, that it's all beautifully written and there's not a lot of delving down to do, but as you develop in rehearsals, you find there's an awful lot more to it and to her. You find yourself needing to ask questions about her past life and why she says things.

"There's an awful lot of my gran in Doris. She was very particular about the house. I can see her and my aunt and my mother in parts of it."

The actress spends the monologue on the floor, crawling from one point to another as Doris goes "from being quite hopeful that she will be all right to gradually thinking she might not be".

Being in a production with two other actors but not interacting with them on stage is strange. "We spent the first few days of rehearsal reading and talking about the characters together. Now we're watching each other as we're on stage," she says.

Hers is the last play to be performed but she won't be getting the rest of the production free. All three sets are on a stage revolve and Chissick wants the two characters not in the spotlight to be on their set throughout the entire show. "The audience will see figures sitting in the shadows," says Sidaway.

Talking to her, you can hear there's still a Teesside twang in her voice. But as Talking Heads' Doris she'll adopt a Yorkshire accent "because that's how it's written" and draw on people from the county she's known for inspiration.

Although Bennett has a home in Yorkshire, she's not counting on him popping into Harrogate Theatre to see Talking Heads. "He's notoriously shy about going to see things, although one always hopes," she says.

In four or more decades, she's had "a fair mix" of roles, she feels. They've included plenty of radio work, including 12 years as Miss Lewis in BBC Radio 4's King Street Junior. "That mix is good because part of the joy of acting is that you have lots of different people to play. It's a part of the challenge you enjoy," she adds.

She'll next be seen on screen in a film called Venus, directed by Roger Michell, who made Notting Hill, and scripted by Hanif Kureishi. Peter O'Toole and Leslie Phillips star as a pair of veteran actors whose lives are upset by a teenager.

"I only have a tiny, tiny part as a nurse. But the film is going to be very good. Peter O'Toole was lovely. I didn't see that much of him, but he was charming," she says.

l Talking Heads is at Harrogate Theatre until March 18. Tickets (01423) 502 116.