`It was like the first day at school, when everyone is looking at each other and something attracts you to one person," laughs designer Liz Quin, describing the fateful day more than 20 years ago when she first met fellow designer, Carolyn Donnelly. From that initial meeting at the Grafton Academy of Design the pair went on to form one of the most successful partnerships in Irish fashion with their label, Quin & Donnelly. This year they are celebrating 21 years in business; and with twice-yearly collections on sale in wear's A-Wear's 11 branches as well as Brown Thomas and Moons stores, the label is still going strong.

In the late 1970s, Carolyn got heartily sick of her first job - designing hacking jackets - and decided to set up a small design studio called Ritzy in Dublin's Harcourt Road. "We were both voracious readers of the English fashion magazines but there really wasn't anywhere selling the kind of clothes we wanted to buy," she explains. Harcourt Road was a little off the beaten track of the few trendy boutiques in existence at that time, such as Mirror Mirror on St Stephen's Green and Hollywood in Grafton Court, but it had the advantage of catching the passers-by making their way home to cheap digs in Rathmines.

Liz, who was working with a clothing manufacturer in Dublin, used to make up her own designs to sell at Ritzy, and when Donnelly decided to move to a larger premises in Trinity Street in 1979, the pair decided to go into business together. It's a time they both remember with great fondness. "We really stuck out because our stuff was very young and very colourful, and we went in for adornment of fabrics," says Liz, while Carolyn adds: "We were just having great fun; we really didn't see it as a business venture as such." Models and those working in the fledgling film industry would flock to Ritzy to stock up. Alison Doody did their photography and U2's Adam Clayton used to hang around and wait for his girlfriend, who worked there. Soon the business was expanding again - the pair were increasingly using suede and leather in their collections and starting to sell wholesale to Brown Thomas and Marian Gale. In 1985, they moved the business to Clarendon Street and re-named themselves Quin & Donnelly, a name which was a little more contemporary than Ritzy and more in line with the designer labels which were emerging at the time. The Clarendon Street operation was a large one, encompassing retail, wholesale and manufacturing spaces - "We were very proud of that store," says Donnelly.

In time the duo were asked to exhibit during London Fashion Week under the Design Studio umbrella, alongside other young designers, including John Galliano, Ben de Lisi and jewellery-makers Gary Wright and Sheila Teague. "The only problem was that we just couldn't run the retail, the wholesale and the manufacturing at the same time, it was just too much," says Liz. Carolyn agrees: "It was also at a time when there was a widespread recession in Ireland . . . We decided to concentrate solely on the manufacture, and then even stopped that."

It was at this point, 11 years ago, that Brown Thomas stepped in and suggested that Quin and Donnelly design a range for their A-Wear stores, following the success of John Rocha's Chinatown label. "Brown Thomas's Deirdre Kelly was very ahead of her time in many ways," says Liz. "Now it's quite common, but she was one of the first to realise that having a designer range can really give a chainstore a bit of a lift . . . It came at a perfect time for us; five years before that, when we just wanted to do our own thing, we might not have taken the opportunity." From the beginning, the pair were concerned that the quality of their clothes should remain high, with a particular emphasis on material; back in the days of Ritzy they would get cloth made up in India and even now they spend 10 or 11 days picking out each season's cloth in Paris. "AWear was looking for a certain quality for a certain price," says Carolyn, and Liz adds: "Which is only possible in today's market if you've got certain volume, and they have that level of turnover."

The label, and the partnership with AWear, has been going strong ever since, even though the look of Quin & Donnelly has changed a little since the early days. "We've been around for 21 years but I would like to think that we're still a contemporary label and aren't just doing the same thing as we did all those years ago. We very much design for the look of the season; we're not the kind of designers who have, for example, always done bias-cut skirts and take that through their collections. We pick up on directions," says Liz.

"That said, a lot of our customers come in to us and say: `I've had a suit of yours for six years and I still wear it to death," Carolyn adds. "We want people to put a suit from this year together with a piece from last year's collection or whatever, and feel it will stand the test of time. That's the essence of a good working wardrobe." Both women feel that their own experience as working mothers has influenced the way they design the collection. "We do understand just how little time you have to decide what to wear each morning when you have kids," laughs Carolyn. "You really need something that will work for you; something that you can throw on and that will look good but won't stand out too much. Most women want to feel and look great but don't want to have to feel self-conscious about what they're wearing." Looking back over the 21 years, the pair are quick to pull out the highlights: "being so young and having our own shop," winning the Late Late Show Designer of the Year award in both 1985 and 1991, and seeing their clothes on the backs of Naomi Campbell et al at the first Brown Thomas supermodel fashion show. The low points are equally clear - Carolyn says: "Only a couple of years ago I had all our contacts from 10 days at the cloth fairs in Paris in a book in my handbag, when it was stolen from a restaurant. It was tough going to get the collection out then." Liz recalls waiting anxiously for one collection to turn up for a show in London - but somebody else's arrived instead. They eventually made the runway with just 10 minutes to spare.

So why do they think they have lasted so long in a notoriously fickle business? "I think it was because of our flexibility," says Liz. "We're very much out there and we're aware that demands have changed." Carolyn adds: "And we've always kept our excitement. We still have a huge interest in what is going on and that helps us to keep coming up with collections we're happy with."