Patricia Routledge is often described as formidable and it’s not hard to see why.

Her resonant tones are those of a woman who won’t stand any nonsense nor tolerate any discussion she doesn’t care for. It is hard to predict what will elicit an impatient sigh from her, but often it isn’t what one might imagine.

The actress is surprisingly breezy at the mention of Hyacinth “It’s Bouquet!”

Bucket, the snobbish social climber she played for five years in sitcom Keeping Up Appearances. Although it’s nearly 20 years since the show finished, she continues to get fan mail about it to this day.

It would be churlish, she says, not to recognise all that the character has brought her and “if it brings people into a theatre for other productions, I couldn’t be more pleased.”

Yet an innocent question about Chichester, the city she has called home for some 14 years, seems to irritate her.

“I suppose I’ll have to admit I live here if you’re going to pursue this line of enquiry,” she says, before going on to describe it as an “absolutely fascinating” place and praising the theatre where she has appeared in productions since 1969. Does she still manage to get to shows there? “Of course I do!” she says incredulously.

“Of course I do. The busman’s holiday is my favourite activity.”

It’s more than 60 years since Routledge launched her acting career and she appears as besotted with the stage now as she was as a child growing up in Birkenhead, when she would put on shows for her parents on New Year’s Eve.

Although hers was not a theatrical family, her parents loved the theatre and she has fond memories of the town’s “superb” music hall, where she saw performers from John Wilton to Arthur Lucan and Kitty McShane. “Those names probably don’t mean anything to you,” she says sadly (and rather sniffily).

She originally thought of becoming a teacher. “My ambition was to teach this wonderful language which you seem to speak quite well but which is abused so badly.

Don’t get me going on this subject!” she warns. But while studying English at the University of Liverpool, she became involved with the dramatic society and that, it seems, was that.

By the mid- 1960s, the young Routledge was appearing on Broadway, winning a Tony award for her role in the musical Darling Of The Day. She even emerged unscathed from Leonard Bernstein’s infamous 1976 flop 1600 Pennsylvania Avenue.

“I kept my head and I kept my job,” she says. “It was a tragic disaster but I was still glad to have been a part of it.

How many people are asked to work with Leonard Bernstein?”

She later won an Olivier award for her part in Bernstein’s Candide, in 1988.

The actress’s time in musical theatre is the subject of a talk she has been touring with the music critic Edward Seckerson for the past six years. Up until that point Routledge’s past as a classically trained singer was what Seckerson describes as one of the best-kept secrets in showbusiness.

But Routledge is keen that we don’t dwell too much on the talk. “If we talk about it here, there’s no point in doing the show,” she comments.

What took her away from musical theatre, I ask?

“Nothing took me away!

I think a career is just a series of opportunities and there were other things I was asked to do that I said yes to.”

It’s an attitude that has taken the actress from the Royal Shakespeare Company to Coronation Street and has seen her work with writers from Alan Bennett (who wrote several monologues in his Talking Heads series especially for her) to Victoria Wood, who cast her as an interfering Cheshire spinster in As Seen On TV.

When did she first become aware of her ability to make people laugh? “I don’t know.

It was always there. I came from a family with a great sense of humour about life.”

She firmly believes in the importance of comedy. “It can help you through many situations. It gives proportion to the many difficult situations that come up in one’s life.”

She might be speaking generally or she may be referring to events in her own life. The actress lost both her parents in her 30s and her younger brother Graham in 1989. She has spoken in the past of her sadness at having never married or had children.

They were not decisions she made. “Life just turned out like that because my involvement in acting was so total.” But she believes it’s important to keep smiling. “Life is comedic if you survive it.”

After the monstrous Hyacinth, a role for which she won a British Comedy Award and was nominated for two Baftas, she went on to play the lead in Hetty Wainthropp Investigates, a character she found rather easier to live with than her predecessor.

“With Hyacinth, you’d put the key in your back and twist it then she’d appear.

But I loved Hetty.

She was no-nonsense, honest, unaffected.”

When the BBC unceremoniously cancelled the show in 1998, Routledge was widely reported to have snapped that the corporation was “run by ten-year-old children”. It wasn’t that she was upset about the show being cancelled she says now but that she was upset at the manner in which it was cancelled.

“We were poised to make another series and for weeks and months no one had the courtesy to tell the director it was being cancelled. They should have said no earlier if they didn’t want to do it any more.”

These days she remains busy but only undertakes work which really interests her. “There’s no point in burning up energy on something you don’t want to do.”

At the moment that means the musical theatre talk, as well as a musical piece about the celebrated British pianist Dame Myra Hess, who famously organised classical music concerts at the National Gallery when theatres and concert halls were shut down during the Second World War.

Does she ever think of retiring?

“Spell it!” she retorts. I assume this means no. “I hope I have the good sense to know when to stop,” she says.

“But I’ll keep working until it no longer interests me.”

* Patricia Routledge is interviewed by Edward Seckerson in A Life In Musical Theatre at The Capitol, Horsham, tomorrow.

Call 01403 750220.

*The show comes to the Connaught Theatre Worthing on November 23.