Nothing could have stopped Ashley Jensen fulfilling her ambition, says Shirley Whiteside

If you grew up dreaming of scoring the winning goal for Scotland in the World Cup Final or fronting a great rock band, chances are that you are still dreaming about your 15 minutes of fame while holding down a sensible job, paying a sensible mortgage, and wondering whether to up your pension contributions.

Occasionally those childhood dreams do come true for those who have determination as well as talent. Actress Ashley Jensen can't remember not wanting to act. She says: ''Ever since I was five years old it used to be, 'When I am an actress . . .' It isn't one of those windswept and interesting things where I had a life beforehand and then decided to act. It has always been just fact that was what I would do.''

Jensen, who was brought up in Annan, didn't let her first taste of rejection put her off. She applied to join the National Youth Theatre when she was 15 but didn't get in. She applied again the following year and was accepted. ''I think my mum thought the National Youth Theatre would make or break me,'' she says. ''I came back saying, yes, this is it.''

Jensen went on to study drama at Queen Margaret College in Edinburgh, graduating in 1989 with distinction, before moving to Glasgow to begin her career. ''I worked quite a lot in the theatre for the first five years,'' she says. ''My first telly thing was Dreaming by William McIlvanney. I was 'girl in betting shop' and I was so nervous.'' Parts in City Lights and Rab C Nesbitt followed before Jensen was cast in Peter MacDougall's gritty gangster drama, Down Among the Big Boys.

She played Claire, the naive young daughter of a successful criminal played by Billy Connolly. Maggie Bell played her mother and Douglas Henshall her policeman fiance. ''At that time any television was a bit nerve-wracking for me,'' says Jensen. ''I knew what I was doing much more in theatre than I did in television. The Billy Connolly thing, I don't think I could actually let myself really think about who this was. I mean, there is just nobody like him.''

In the years that followed more theatre and television roles came her way. She played Heather in two series of Roughnecks and Rosie in May to December, cropping up in The Bill, The Tales of Para Handy and Dangerfield along the way.

In spite of her many theatre and television credits Jensen did not make her film debut until last year. But if you are going to make a movie you should start with the best and Jensen certainly has winning a part in Mike Leigh's recent movie, Topsy-Turvy. ''It is a period piece about Gilbert and Sullivan,'' says Jensen. ''I play one of the chorus girls in the Savoy Opera Company which was brilliant. Mike Leigh is someone I have always wanted to work with.''

Last year she landed the part of PC Sue Chappel, a regular character in the BBC's Saturday night police drama City Central. As the part had originally been written with a 20-year-old Mancunian in mind, Jensen was surprised and delighted to get the job. ''I went in and did the best Manchester accent I could do. ''It was a bit like that,'' she says slipping into a very creditable northern accent. ''They got me back to read with Stephen Lord who plays my partner. Now he is the real thing and I was a bit embarrassed but I just went for it.''

The natural rapport that developed between Jensen and Lord during the casting sessions convinced the producers that Jensen was right for the part. Shortly before filming began they even asked her to drop the northern accent to introduce some geographical variety to the main cast of characters.

Although Jensen had worked hard to perfect her Manchester twang she was pleased to play the part in her own accent. ''It brings a whole different culture really,'' she says. Jensen undertook a two-day intensive course in order to learn the mechanics of being a police officer. ''We had to learn how to work the radio, how to stand, how to speak to people, when to use the baton, when to use the CS gas and we went out on the streets with real police officers,'' she says. ''That was a real eye-opener and I started looking at things differently. That man standing on that corner in a rather dubious fashion is probably not standing there because he is waiting for a bus, it is because he is a pimp. I started to see things I hadn't really noticed before.''

In ''Paradise Lost'', last week's City Central, Jensen delivered a powerful and sympathetic performance. Still undecided about her unplanned pregnancy, Sue found herself kidnapped in a tunnel by Dennison, a paedophile played by John McArdle.

''It was a cold, dark, dusty, dank, really unpleasant place to be,'' says Jensen, ''which from my point of view helped me to get the feeling of the situation. You find yourself on this wavering little line of being asked to cry at any minute. I am not at the stage yet where I can laugh with the camera crew and then suddenly do it. But that is my job. I have got to concentrate that bit harder to get to the place emotionally where I can do it.''

n Ashley Jensen stars in City Central (BBC1, 8.15pm)

Saturday nights.