Let's be frank - this is not a great fashion moment. Repetition and plagiarism are two accusations which can be justifiably levelled at most designers, those who are content to return time and again to the same handful of ideas. Skirts up or skirts down - does it really matter anymore? Hem length has ceased to be the barometer of fashion and nothing has taken its place. The need for a fresh approach has never been so urgent.

How odd, therefore, that novelty should be found right now not in mainstream fashion, but in the field of accessories. While every manufacturer and retailer offers almost exactly the same line of trouser-suits and dresses, the range of hats, bags, gloves, scarves and even hosiery grows steadily wider and more inviting. Shops such as Monsoon and Accessorize have become business leaders because the consumer is more interested in buying bits and pieces than a new outfit.

Two leading accessory designers have strong Irish connections; Philip Treacy and Lulu Guinness. Galway-born Treacy has become one of the world's most successful milliners during the 1990s, responsible for the extraordinary revival of interest in hats during this decade. After attending the National College of Art and Design in Dublin, he moved to London's Royal College of Art, where he worked with the likes of John Galliano and Rifat Ozbek while still a student. A year after graduating, he had already opened his own showroom on Elizabeth Street in London, which still operates as Treacy's headquarters. In 1991, he also began a long-standing professional relationship with Karl Lagerfeld, producing millinery for the Paris-based designer's own line as well as for Chanel. In 1991, he received his first British Accessory Designer of the Year award, which he has since claimed three times, most recently in 1996. By 1992, Philip Treacy had started to produce a diffusion line for Debenhams, originally a collection of hats but now covering a vast range of accessories, which he had introduced into his couture line last year. Examples of his work featured in 1997's Cutting Edge fashion exhibition at the Victoria and Albert Museum in London, and his designs were also used to effect at the 1996 Biennale di Firenze show.

What marks Philip Treacy apart from other milliners is his imagination, since he uses materials and forms not usually seen in hats. Whether laser lighting or brilliantly dyed feathers soaring into space, the basic ingredients always surprise. A Treacy hat is not for the timid; it tends to grab attention and is therefore best worn with the plainest of clothes. His fashion shows, held once a year in London, are invariably thronged and his collections rapturously received as each successive hat is met by a burst of applause.

Thanks to the brilliance of his creativity, Philip Treacy has no problem attracting some of the world's finest models such as Naomi Campbell and Kate Moss to participate on these occasions.

The same names are likely to be found carrying handbags made by Lulu Guinness. As the surname suggests, her husband Valentine is a member of that family, but Lulu Guinness tends not to trade on such connections, relying instead on her own considerable talents. Aside from a year's foundation course at art school, this designer is entirely self-trained; in 1989 she left a job in video production to start her own business from the basement of her home in west London.

By 1995, she had opened her first shop - also in Elizabeth Street - and her principal salon is now on Ledbury Street in Notting Hill.

Also like Treacy, she often collaborates with fashion designers, having produced bags for the runway shows of Colette Dinnigan, Mark Whitaker and Clements Ribiero, among others. Her ever-expanding client list includes Elizabeth Hurley, Christian Lacroix, Madonna and Dame Judi Dench, for whom she designed a clutch bag to carry to last year's Oscar ceremony. And, again like Philip Treacy, since 1995, she has been producing a diffusion line for Debenhams.

A spirit of retro glamour informs all of Lulu Guinness's work. Her signature piece is the floral handbag, designed to look like a flower pot in bloom. Two examples - the "florist basket" and the "violet hanging basket" are now in the permanent fashion collection of the Victoria & Albert Museum.

All of her bags are handmade in England by a team of women chosen for their skills; the eldest member of this group is aged 85.

Lulu Guinness's handbags and the full range of hats and accessories designed by Philip Treacy are now available from Louise Kennedy's new outlet at 56 Merrion Square in Dublin, while both designers' diffusion lines are carried by Debenhams at the Jervis Centre, Dublin.