Her glare was enough to turn Basil Fawlty’s blood cold.

Whatever he was getting up to, whether it was insulting German guests or trying to outwit the health inspector, a shrill cry of “Basil!” from his shrewish wife would strike terror into the unfortunate Torquay hotelier.

Then there was the nasal laugh, once described by John Cleese as sounding like “machine-gunning a seal”, and the endless gossipy phone chats to her friend Audrey. “I know, I know,” droned Sybil Fawlty, cigarette in one hand, phone receiver in the other, flicking ash somewhere in Basil’s direction.

If Fawlty Towers had been a 21st century sitcom, Sybil’s catchphrase would be merchandise gold, probably appearing on T-shirts, car stickers and mobile phone ringtones.

As the archetypal harridan wife in the classic 1970s sitcom, Prunella Scales created a comic icon. While the show was written by her co-stars John Cleese and Connie Booth, much of the credit for its lasting success goes to Prunella’s hilarious interpretation of shrewish Sybil, the woman who forever scuppered Basil’s schemes and smoothed over the cracks of his shambolic attempts at hotel management.

Now 76, Prunella Scales has since become one of the grand dames of British film and theatre. These days I’m more inclined to think of her as a leftie luvvie than the coiffured creature giving Basil the evil eye 30 years ago.

In a publicity still of her latest role she’s a confused and frail-looking elderly woman in a faded dressing-gown. Prunella plays a woman waiting for her daughter to ring on her birthday in Gertrude’s Secret, coming to Leeds this month. It’s a series of monologues; some funny, some sad, some with twists.

“It’s very cleverly written,” says Prunella. “There are twists which I won’t give away, but I will say that each monologue is a joy. I can’t say I prefer monologues, because I also enjoy working with other actors on stage. Each brings its own problems and pleasures.” Born in Surrey, Prunella inherited her mother’s love of acting and cut her teeth in West Yorkshire.

“I have a lot of affection for Bradford,” she smiles. “My grandparents lived there, my grandfather owned a textile warehouse, and my mum often talked of it. We’ve been up many times to your lovely old theatres. And of course my husband was born in Bradford, albeit by accident.”

He may only have spent the first few weeks of his life here, but Bradford likes to claim actor Timothy West as one of its own. He was born here while his father was appearing at the former Prince’s Theatre in the city. His parents, actors Lockwood West and Olive Carleton-Crowe, were members of a troupe of actors which had arrived in Bradford with a touring production when their son was born at a nursing home in Manningham Lane in October, 1934. Weeks later the family had moved on but West appears to remain proud of being born a Bradfordian.

“I’m very proud of my northern roots,” he recently told the T&A. “I love Bradford and very much enjoy the touring life, playing to regional theatres.”

Prunella and her husband have championed Bradford causes over the years, most notably backing the T&A’s campaign to save Little Germany theatre The Priestley, now Bradford Playhouse, from closure a few years ago.

When I tell her the historic theatre is once again facing tough times, having gone into administration earlier this year, she sounds genuinely concerned.

“It breaks my heart to hear about our small theatres struggling to survive. As well as playing a vital role in community life they’re our heritage and should be cherished. I hope it gets back on its feet very soon,” she sighs. “We need more funding to maintain theatres but this government pays less into performing arts than any other country in the EU, apart from Portugal. Isn’t that terrible?

“We lost the old Theatre Royal in Huddersfield but we still have the Lawrence Batley, thank goodness.”

Like many actors of her generation, Prunella goes a bit misty-eyed at memories of the pre- and post-war repertory theatre companies that kick-started acting careers.

“Theatres need rep and touring companies, and so do actors. It’s where our generation learned their job. We should have three-weekly or fortnightly rep; it’s wonderful training,” she says. “We toured the world with full productions of Shakespeare. You’d never get funding for that now.

“I did weekly rep in Huddersfield and I have wonderful memories. I stayed in digs run by a landlady called Mrs McKay. When I was going out she’d say to me (adopts pitch-perfect northern accent), ‘I’ll put you down a double put-me-up love’; I don’t know who she thought I was going to be bringing back but she clearly didn’t have a problem with it! “There were lots of those landladies back then. They looked after us.”

It brings to mind recent stories on the T&A’s Past Times page of former Coronation Street actress Pat Phoenix staying in Bradford digs while appearing at the Prince’s Theatre.

Prunella herself went on to appear in Coronation Street in 1961, playing bus conductress Eileen Hughes, fighting Florrie Lindley for Harry Hewitt’s affections. In Gertrude’s Secret she appears with former Corrie actors Angela Griffin, who played Fiona Middleton, and Angela Lonsdale, who was PC Emma Watts.

I bring up the problem of actors moving away from a role they’re associated with in an attempt to get Prunella to talk about the role she’s most famous for. I’d heard that she could be a bit prickly whenever the name Sybil came up in conversation so this may just be a way of bringing up the ‘S word’ in a roundabout kind of way.

She neatly sidesteps it. “It’s great good fortune to have success in a soap. It’s hard work, one mustn’t knock it, and if you’re lucky you can make your name,” she says. “Having names in a cast means people take a step towards coming along to see you, even if they wouldn’t normally go to the theatre.”

With a deep breath, I go for it and ask about Sybil and whether Prunella has managed to leave her behind.

“I was already well known from Marriage Lines (1960s sitcom she starred in with Richard Briers) by then and, to do the British public credit, they don’t tend to ask you to keep doing the same thing over and over again,” she says. “We’re very lucky in this country that we can work in all four mediums; theatre, film, television and radio.

“Actors shouldn’t be pigeon-holed. That’s why rep was so valuable; it developed our skills so we could take on a wide range of roles.”

Not wanting to dwell on one role is fair enough really. Fawlty Towers lasted for just 12 episodes, a small slice of Prunella’s working life, and since then she’s played everyone from the Queen to Jane Horrocks’s batty mother in the Tesco adverts.

Her films include The Boys From Brazil, alongside Laurence Olivier and Gregory Peck, and Emma, with Gwyneth Paltrow, and her TV credits include Mapp And Lucia and After Henry, which originated on radio.

She has played several Queens; in stage show An Evening With Queen Victoria, TV documentary Waiting For Victoria and Alan Bennett’s A Question Of Attribution. Some say that her acclaimed role as Queen Elizabeth II in Bennett’s play – the first time a reigning monarch had been portrayed in a theatrical production – and the subsequent TV film version should have made her first choice for the title role in 2006 film The Queen. When someone has had a career spanning more than half a century and they’ve worked with everyone from Olivier to Bennett, you can only scratch the surface in a 15-minute phone conversation. Suddenly my time slot is up and Prunella has another call waiting.

“Is that enough for you dear? Listen, come and see me in Leeds and we’ll have a nice chat.”

Don’t worry Pru, I’ll try not to mention the ‘S word’.

Gertrude’s Secret runs at the Leeds Grand Theatre from Tuesday to Saturday. For tickets ring 0870 1214901.