Smart Shazzer - the boss in control

The mounting pressures of the job ought to have cowed the doughtiest soul. Not Maguire. She soon impressed people with her cool self-assurance and an unflagging will to get things right. The novelist Sebastian Faulks, on set as an extra for the "Bridget's speech" scene, recalls, "She wasn't at all bossy, but obviously in control. Sort of Erich von Stroheim in a skirt. You'd have thought it was her 15th film, not her first."

As Sharon tells it, she was generally too busy to panic. "Once I started, I focused entirely on the work, which would be 17 hours a day. The only time I got worried was in the cold dead of night, eating crisps in my pyjamas and thinking, 'Oh Jesus - Miramax are flying in tomorrow, I've got to meet Harvey Weinstein.' That was a bit terrifying." Among others she credits her close friend and fellow director Anand Tucker for keeping her sane: "He's been through the filmmaking process, and understood when I went on about the exhilaration and terrors of it."

She wasn't always going to be a film-maker. Acting, rather than directing, was her first passion, and she still delights her friends with her gift for mimicry. It derives, she thinks, from the speech and drama classes she attended with her sister from the age of four. At Aberystwyth University in the early Eighties she continued to tread the boards, though found herself typecast: "I always played the whore," she says. "I don't know why that was."

Her finest hour came in a production of The Threepenny Opera. "I remember having to say to Mack the Knife, 'My name's Fanny, and when I'm out in shop doorways I don't wear any.' I guess he must have asked whether I wore knickers."

Reluctantly, she abandoned the idea of becoming an actress, and cast around for an alternative career. After a year's teacher training - "My mum always wanted me to be a teacher" - she moved to London, where she worked at Penguin Books for five years, first in the publicity department ("just like Bridget") and later as a copywriter. She did a year's postgraduate course in journalism at City University, then got a research job on The Media Show, at which point she realised she wanted to direct. "It seemed like a good idea - images and music and words." In 1991 she joined the BBC as a director and producer for The Late Show, and graduated to documentaries for Omnibus and Bookmark. A lucrative spell making commercials prepared her for the bottom-line economics of feature films.

With Bridget already a cast-iron hit, she has started preparing for her next project, an adaptation of a little-known novel called Mail by Mameve Medwed. It concerns the travails of a thirtysomething Bostonian writer struggling with her career and falling for a postman - a story likely to satisfy audiences hungry for the next Ms Jones. Is Sharon in danger of becoming typecast (again)? "I have had magazines ringing me up and asking what I think might be the future of romance. All of a sudden I am an expert on sex and the single woman."

So what have the three years on BJD taught her? "I learned a lot about comedy," she says, "and I also learned that quite often the director has to be a focus of contempt - there has to be one, so you take it on." For all that, she seems to have emerged happier and wiser from the experience. "I think if I was good at anything it was listening to people - to actors. Hugh, Colin and Renée all came up with good ideas about their roles, and how they could improve the film. If you've got the time, you should use it to listen. Some film-makers would see it as a weakness, but to me that collaboration was so important."

She's also learned to deal with the Press, and my attempts to lure her into indiscretion are met with peals of outraged laughter. No, she certainly won't tell me the story about the balconette Wonderbra, or about the day she and Hugh Grant spent sneaking up to draw penises on the arms of various cast and crew. "Just say, 'When asked, she looks uncomfortable'," Sharon smirks, looking anything but. She remains remarkably self-deprecating about the limelight. "I wasn't prepared for the level of attention. At the New York premiere of Bridget I stepped out of the limo and all of a sudden there was this blinding volley of flashbulbs. These photographers were all screaming at me: 'Hey! Shannon! Shannon! Over here!'"

Something tells me no one will get that name wrong again.