HER debut film performance is said to have reduced Sir Sean Connery to tears - not once, but twice. When I meet the young actress, Paula Sage, for lunch in the Travelling Spoon cafe in Glasgow, where she works part-time, it takes her no time to have the same effect on me. Except on this occasion the tears are of laughter.

Less than two years ago, Sage, who has Down's Syndrome, burst into the public consciousness when she starred, to great acclaim, alongside Kevin McKidd in the award-winning film, Afterlife. More recently, viewers of BBC Scotland's River City have known the 25-year-old as feisty Donna McCabe.

In real life, Sage is unlike her Glaswegian character: she is warm, bubbly and witty. She reminds me of Winnie the Pooh's friend, Tigger. When I ask how an actress like her, with Down's Syndrome, is treated by her thespian counterparts and production crew, she replies casually: "Oh, we're all treated the same. Everyone is treated equally. But, then, we (Down's Syndrome actors) are different. We're more special, we've got an extra chromosome, after all, " she adds without so much as a grin. A few seconds later and she is in creases laughing. As am I.

Later this week Sage, who left River City in March, returns to television screens for a two-episode appearance, to be aired on December 23 and 27. Featuring in a storyline centred on her on-screen father, McCabe, a local gangster, who is once again embroiled in illegal goings-on, Sage says she relished the opportunity to be back behind the camera and among her River City friends and colleagues again.

Sage was approached to star in the Glasgow soap by BBC producers after they saw her appearance as Roberta Brogan in Alison Peebles's Afterlife. The 2003 film went on to win awards, including the Audience Award at the 2003 Edinburgh International Film Festival. "I can still remember the day I got the call from River City. It was a Friday. I was shell-shocked. Then I thought, 'Excellent, let's go for it.' I had watched River City before they asked me to join, I was a big, big fan. I loved it. I still do."

While keen to act again in the future (throughout our interview she asks me a number of times to write that she wants River City producers to hire her again), Sage says she is happy working in the Travelling Spoon, a travel agent and cafe in Glasgow's Trongate. It is run by Unity Enterprise, a social, education and employment charity initiative that offers training and personal development to young unemployed people, including those with physical or mental disabilities.

Sage is very much at home behind the sandwich counter and travel desk with customers and colleagues. Her broad smiles and impish sense of humour are never far away. One colleague tells me Sage keeps a keen eye on the male passers-by. Sage vehemently denies this. "No, I don't. I just do my job, I'm a professional, " she laughs. "I love it here, absolutely love it. It's great fun and, well, they all love me. But, " she says turning serious for a moment, "I would love to do more acting and will do so."

Her role as Roberta Brogan won her a number of awards as well as high praise from film critics, a rarity for any actress. Among the accolades was a Scottish Bafta Award 2004, for Best First Time Performance. It was recognition she richly deserved, given the demands of the role. Her character lives with an over-protective mother called May, played by Lindsay Duncan, while her journalist brother, played by McKidd, lives away from home.

When May is diagnosed with a terminal illness, the family, including Sage's character, all had to consider the future. The film dealt with a variety of issues, including the challenges of singleparent families, terminal illness and learning difficulties. The film also called on Sage to deal with her own appearance and identity as a woman with Down's Syndrome. "When I had to do sad scenes in Afterlife about not liking my face, or the way I looked, I thought about Maurice Gibbs's death to make me cry. He died while we were filming. I love the Bee Gees' music. It was really sad."

Today, Sage lives with her parents, Alan and Mary, in Cumbernauld. It was at her local theatre group that she was first introduced to acting and then spotted years later by Peebles.

Even though Sage has enjoyed success in her career, she still attends the 1 in a 100 Theatre Group every Friday night. "Alison Peebles and Catherine Atkin (of Afterlife) came to the theatre group. They already had actors for the roles anyway, but they saw me acting at the club and thought that I'd be quite good for the role of Roberta.

"It was a lot of work, " she insists with a smile and a jovial prod in my side. "Filming took around six, seven, maybe eight weeks. I had to get up very early and wasn't home until 10pm at the earliest. It was far from glamorous, " she says, "but it was worth it. I loved it."

FOR YEARS, CAMPAIGN GROUPS HAVE fought against the stigma of disability in the acting profession, arguing for better representation of disabled individuals on television and in film, not only in scripting such roles, but (perhaps more crucially) casting more actors like Sage, Julie Fernandez, who played a wheelchair-using employee in the BBC2 comedy series, The Office, and Steve Varden, an actor with cerebral palsy who appeared in Cloud Cuckoo Land.

It is a campaign to which the Sage family are committed. As an ambassador for Enable and Mencap, Sage hopes to see more actors like her do well in the entertainment business.

"I think more Down's Syndrome people like me should go in for acting. Being Down's Syndrome doesn't mean you cannot act. My friend, Marianne, is one (Down's Syndrome) person I know who would love to become an actress, but it is really difficult for her."

Her father says the main problem for disabled actors is the shortage of roles. The opportunities for actors such as Paula are limited, he says. "I'm not sure what the future holds for Paula; it will depend on roles opening up.

"People with disabilities are part of the community, and film and television are there, in part, to represent communities, so there should be more roles for them to act."

Last year the BBC launched an GBP800,000 campaign to improve the way disabled people are represented on television. Among the targets, series such as Holby City and Bargain Hunt have to show at least one disabled character or contributor a year. In addition, one in every 50 quiz and game show contestants should be disabled, and two in 100 extras in BBC1 dramas should be disabled actors.

Job opportunities might be improving for disabled thespians, however slowly, but the broader issue of how the public perceives these actors still needs to be addressed. In Afterlife, Sage's performance captivated audiences, not only because of her Down's Syndrome, but because Sage delivered her lines with effortless charm and perfect timing. In otherwords, it was her talent, and not her disability, that so impressed viewers.

Speaking at the time of the film's release, directorAlison Peebles said: "Paula's a naturally-gifted actress, and I think she could easily go on to play characters in comedies or dramas that have nothing to do with Down's Syndrome."