JACQUELINE Pearce had decided not to dress for our interview. Instead, she was residing in a corner of the theatre foyer, a red robe wrapped around her body, slippers on her feet and a roll-up cigarette on her lips.

Not exactly the figure grew to love and loathe as the ever-so-evil Servalan in the science fiction TV series Blake's 7. Her lip-smacking performance as the wicked space commander, in pursuit of Blake and his ragtag band of renegades through outer space, made an indelible impression on many a young lad unused to the sight of such a woman, hair cropped to within an inch of its life and clad in various figure-hugging gowns.

But she's come in early to put on her stage make-up before the interview, hence her semi-clad appearance. Pearce, hair greyer but still shorn, looks up from reading the Daily Mail latest about the war against terrorism and replies, in answer to my "how are you?" inquiry, "I'm okay, but I'm worried about the world".

Oh dear, you think, I'm in for half-an-hour of gloom and doom. Far from it. Despite her understandable anxiety about the state of the world, she's prone to throw back her head, widen her eyes and emit a raucous laugh at every opportunity.

Perhaps, I venture to suggest, performing on stage takes her mind off the worries of the world. "For the few minutes I'm on, I suppose it does," she says.

She's appearing in a revival of J B Priestley's Dangerous Corner at West Yorkshire Playhouse in Leeds prior to a run in London's West End. Her role is not a big one - she disappears for a large portion of the play ("I make the interval teas") - but a crucial one. And despite the array of pretty young things, both male and female, adorning the cast she can still command the stage whenever she's on it.

She didn't know the piece before, not realising what "a wonderful play" it was. The director has updated it and put it in a contemporary setting. And this works, she assures me. "You will love it. I guarantee," she says. "Audiences are loving it. It's so lovely to do something an audience gets into and appreciates. It's the happiest company I have ever been in, and because I'm as old as God, I know of which I speak."

You might anticipate she'd be happy about her participation in Blake's 7 which, more than 20 years since the series ended on BBC1, is still being shown (on cable - where else?) and has accrued a devoted, not to say fanatical, following. The truth is that Pearce has no interest in science fiction whatsoever and only watched episodes at the time "if I was in it". The character of Servalan, commander of the forces hunting down Blake and his rebels, was conceived as a man. One day writer Terry Nation, the man who also invented the Daleks, decided he would be better played as a she.

Pearce was appearing in the West End in Simon Gray's Otherwise Engaged at the time and, so the story goes, only got the part after another actress in that production turned it down. Now it's impossible to think of anyone embodying Servalan so thoroughly as Pearce. Certainly she was a strong woman when they were few and far between in TV series. As such, she had the same effect on fragile male egos as leather-clad, kinky-booted, karate-chopping predecessor Cathy Gale, played by Honor Blackman, in The Avengers.

Pearce's influence on Servalan extended to the way she looked. "I had grown my hair very long, got bored and cut it all off. I'm that sort of girl," she recalls.

When Blake's 7 ended - and it was only produced between 1978 and 1981 - she was offered a lot of strong women in science fiction "which I found quite boring". Now, she adds, she's getting the chance to do more comedy, something she loves. Perhaps she's just a softie at heart, naming Jane Eyre as her favourite novel and Mr Rochester as the most romantic man in literature. But given the cult status of Blake's 7, she finds it impossible to shake off Servalan totally, attending fan conventions "if there's a slight hiccup in the cash flow".

Pearce was put in the direction of acting while at convent school. "The woman who ran it was a dipsomaniac and I spent all my time getting her bottles of gin," she recalls. "But there was a lay teacher, a brilliant teacher and actress who couldn't act herself because she had very bad vision and couldn't see across the stage. She suggested I should be an actor. I had to persuade my father that actor was not a euphemism for prostitute and to let me audition for Rada."

The stage remains her first love. "I don't know why because it's hell on the whole. Perhaps it's the adrenaline rush," she says. "But I'm very boring. I think I want what any actor wants - to do good work with good people. That's what I am doing with Dangerous Corner and that doesn't happen very often."

Dangerous Corner continues at West Yorkshire Playhouse, Leeds, until October 13. Tickets 0113 213 7700.