Thanks for being Beverly

Steadman is delighted that Orton's 36-year-old play hasn't dated. Lovingly written in rich, ripe language, it is largely remembered for the shock value of its comic handling of sex and crime - 1964 was only a year after 'sexual intercourse began' (as Philip Larkin put it), after all. 'We've had people tell us they saw the play the first time round and didn't realise everything that was going on in it,' she says.

'Now that we're more used to seeing different sexualities and everything else that's suggested in the play, it looks very different.'

Mercifully, Steadman has absolutely no wish to counterbalance her comedienne image with the old off-stage 'tears of a clown' routine.

Indeed, she guards her private life zealously, which is no surprise considering that her 1996 split from Mike Leigh after 23 years of marriage made tabloid headlines. She winces when I allude to it. She left their North London family home to live with actor Michael Elwyn, whom she met on the TV series No Bananas. Although she still regularly sees her two sons, Toby and Leo - one of whom is an animator, the other at film school - they are less than happy at being mentioned. 'They tell me: "Interviews are about you, not about us",' she says.

She presents herself as refreshingly uncomplicated and reveals an unusual honesty when she says that part of her pleasure in acting lies in the applause. That may sound blindingly obvious, but almost no other actor is willing to say so on the record. They'll talk about empathy or compassion or creativity, but few will admit to the visceral pleasure of riding the waves of audience approval.

That's one reason why she prefers theatre to TV or film. 'I'm calling the shots. There isn't someone cutting, or shooting me from a particular angle, it's me and I can hear when an audience is getting it. It's usually a man with an especially dirty laugh. When you hear that, it's as if they're saying, "Go on, give me more..." That relationship sparks me off: the rapport is so exciting. Of course, by the same token, when the laughs don't come, you know you're dying out there.'

She learned about making people laugh very early. Her sisters were much older than her so she played as if she were an only child: for example, putting her dolls to bed, she would do all the voices. At the age of seven, she impersonated the people next door, who were Scottish - a completely distinct accent from everyone else she knew growing up in post-war Liverpool. Although her home life didn't exactly scream high drama - her father worked in an office and her mother was a housewife - her parents encouraged her impersonations.

'That's what I thought acting was: being someone else and making people laugh. They'd say, "Ooh, you are clever." That gives you a lovely warm feeling.' She grins broadly. 'Now multiply that by a thousand people!'

Around the same time she fell in love - with the legendary comedienne Hylda Baker, who was in her very considerable heyday. Steadman admired her unreservedly for her guts, timing and comic invention, and has clearly been influenced by the scale and strength of Baker's characterisations.

Steadman's trademark is not just an ability to create unusually bold characters but to rescue them from caricature by cramming them with telling detail.

Her other acting revelation came through an enlightened schoolteacher. Normally terrified of reading in class - only recently has she conquered the terror that besieges her at the initial read-through of a rehearsal period - she experienced a literary epiphany when her class of 12-year-olds was introduced to the passions coursing through Macbeth.

'My best friend Hilary Chadwick was Macbeth and I was Lady Macbeth and we did the scene where she tells him, "Give me the daggers." Somehow we knew what it was about and became completely involved in it. Afterwards, the teacher just stared at us and said, "Girls, that was... wonderful." Absolutely nobody laughed. Even now I can remember exactly what it felt like.'

Two years later she was going regularly to a youth theatre where she discovered a gift for improvisation. By the end of grammar school, she knew she wanted to pursue acting as a career, put on her best coat - 'turquoise with a little blue collar' - and went to a director at Liverpool's Everyman Theatre for advice. He pointed her away from more traditional drama schools and towards London's E15 Acting School.

That proved to be a wise decision. After graduating, she played Sandy, the girl who has sex with the art teacher, in The Prime of Miss Jean Brodie at the Theatre Royal, Lincoln - and hasn't spent too much time signing on ever since.

Like all actors who yearn to work (90 per cent are unemployed at any one time), she reckons she's only good at being unemployed if she knows that there is something lined up in the not-too-distant future. Conversely, she dislikes long runs. In 1992 she originated the role of the blowsy mother in The Rise and Fall of Little Voice, directed by Sam Mendes, which did four months at the National Theatre followed by five months - 'a killer' - in the West End.

Further contradictions stalk her. She believes in knowing what you're good at and sticking to it, but eschews safe choices. Last spring she dropped her wage level to the Equity minimum to take a part in Chunky Monkey, a first film by Greg Cruttwell, which she describes as the most bizarre, the darkest and funniest script she's ever read. 'It cost £128,000, which is normally the coffee budget.'

Breaking the habit of a lifetime, she's dying to see it. Normally, she hates watching herself. 'It's like hearing yourself on tape, or seeing holiday snaps. All you can think of is: "Oh my God, look at me in that awful top." It's pure vanity, of course. I look at myself and I see this middle-aged woman, not the character.' It's also partly down to experience which has made her ever more self-critical. 'When I played Sandy in that first job, I knew the character was Scottish and I just did it. Now I'd want to know which part of Scotland, I'd get tapes and everything. When you're a kid, you don't know to be scared. Now I'm older, I'm more cautious, but more investigative.'

When I ask her what she would do if, for some inexplicable reason, work suddenly dried up, she is genuinely at a loss. 'Part of me thinks I'd just get a little cottage but then...' She either cannot, or will not, let herself think about it. Instead, she goes honest on me again.

'There's a certain comfort in being admired for what you do. To be forgotten would be very hard. It's part of the whole acting thing, the joy of entertaining.' She gathers her thoughts. 'Those times when you're in a really good show and afterwards you go and have a drink and a laugh, that feeling of elation and celebration would be really hard to leave.' Happily for us, I don't think she's going to get the chance.