With her first nude scene in the offing, Barbara Dickson has no need to worry that her 1970s Top of the Pops image has stuck, says Eddie Gibb.

A knot of press photographers is hanging around on the waterfront, while a blonde in a short skirt poses patiently. Out across the bay, white-sailed yachts cut through the water which sparkles in the sunlight. Clearly puzzled, an elderly gentleman stops to ask who the stellar presence is at the centre of all this paparazzi attention.

The glamorous seaside location is Largs, the traditional holiday town on the Costa del Clyde where generations of Glaswegians have gone doon the watter for Fair Fortnight. And who is the celebrity? Why Barbara Dickson, the Dunfermline-born singer and actress who is here to film BBC Scotland's forthcoming comedy/drama The Missing Postman.

Granddad has clearly heard of Dickson - indeed, he is moderately impressed - but it is perhaps no surprise that he did not recognise her without a little gentle prompting. "People take a photograph of you when you are on Top of the Pops and it stays with you for ever," Dickson acknowledges later, once the photo-opportunity is finished. "It is the most destructive and negative thing to happen to any performer - it's like seeing a tiny little bit of the picture but that snap becomes your whole career."

And that snapshot, for most people, is of a bubble-permed singer from the 1970s belting out middle-of-the-road hits such as January, February or the theme from the movie Caravans.

However, in career terms, Dick son is a survivor. She is approaching her 50th birthday just as her professional credibility has hit an unexpected upward arc. The shagpile hair-do of yesteryear has been replaced by a sleeker style; she wears a pintripe suit of charcoal grey. Round, wire-rimmed glasses make her look like a character in the movies who shakes out her hair and rips off her specs, revealing the glamorous dame who has been concealed beneath a frumpy librarian exterior all along.

In a sense that is exactly what Dickson has done, except the medium has been television. Her role as Anita Braithwaite in the punchy drama Band of Gold, about a group of Bradford
prostitutes, provided more street credibility than she has enjoyed since leaving Dunfermline, aged 17. The salty language and uncompromising portrayal of men at their most inadequate, together with a surprisingly feminist subtext for a Sunday night on ITV, made Band of Gold one of the most popular dramas of 1994 and earned it a second series earlier this year.

"It was great to be offered that because Anita wasn't someone who people would ever connect with me," says Dickson. "But because I'm working class and come from a very ordinary background in Dunfermline, I thought I can do this, I know what these people are like."

Maybe, but of late she has been occupying a large house in leafy Lincolnshire with a television executive husband and three children. So how did she get into the character of a woman who, though not a pros titute herself, was very familiar with street life? "It's an old showbiz chestnut, but they say you put on the shoes and you know who you are," says Dickson. "Anita was a definite slingbacks girl. She wore tight leggings, applique T-shirts and fluffy jumpers - if you put that gear on it's actually quite easy."

Having played tarty to some acclaim, Dickson was offered the role in The Missing Postman as the love interest opposite Likely Lad James Bolam, a postman who is made redundant and cycles the length of Britain on a final, Pony Express-style delivery run. Although described by its producer as a "delightfully warm" story, Dickson as an Arran landlady offers Bolam more than B&B. Her first nude scene may further help nail the bland image.

With 50-year-old Prime Suspect star Helen Mirren gracing the front of last week's Radio Times wearing only a remarkably well-preserved birthday suit, it seems as if older actresses are stripping off all over the place.

"Helen Mirren is a good actress but she also turns men on," says Dickson. "I've never been a sex symbol, so it's nice to become one when I'm older. When I was young I despised all that but now I think it's rather clever of middle-aged women to be successful and attractive, because there's plenty of middle-aged men around. I find in the past six or seven years I have been much more confident and that is affecting people's perception of me."

Despite record sales which ran into millions over a 15-year singing career, at the start of the 1990s Dickson was close to despair at the way she had been shunted into a musical backwater, where it looked as if she was destined to bob around for ever more. An album of Bob Dylan songs in 1992 was a desperate attempt to regain some credibility, as she vainly tried to make a connection between her own folkie roots and Dylan's protest songs. It would not wash and prompted only an outbreak of tittering among the hipsters of the music press.

"Because I'm not controversial, I was viewed as being boring," she admits. "Now I would be lying if I said that didn't bother me, but I would rather be boring than be Paula Yates - that would be completely hideous. I didn't feel like a normal pop star anyway because I'd been around a long time - and pop stars by definition tend to arrive and disappear. But my longevity as an artist meant that people were growing old with me and I didn't want to be someone who had been around for ever."

Ironically her second big screen role was in Taggart in which she played a raddled former pop star. But the point is that actors play a part, while as Barbara Dickson, singer, she had become imprisoned within her own image. Having lived to regret that particular gilded cage, Dickson is determined that her acting career is not derailed early by making any more wrong turns. "I'm not likely to do anything which is kind of end-of-the-pier because I can see myself being plummeted into the abyss of being a middle-of-the-road boring television actress," she says. "I can't afford to be anything other than a wonderful television actress who's deeply talented and very, very beautiful. This is my ambition - I'll let you know how I get on!"

"The Sunday Times", October 1996. Interview by Eddie Gibb.