IT'S time to shake out the Arran sweater, preen the beard, mumble about Irish ancestors, swill pints of ale and remember how to Morris dance, for the Hong Kong Folk Festival is on us again. This year's festival is the 10th, and continues in the same vein as earlier years with local stalwarts performing alongside a selection of overseas artists. The traditional Irish Ceilidh on November 6 will be led by The Doonan Family Band from northern England. Other visitors include Les Barker and Derek Brimstone (both performing comedy and music), The Singing Kettle and Major Mustard for the children, and Martin and Jessica Simpson, British musicians living in the United States. That the festival mainly consists of British and Irish music is not much of a surprise to those who have been to the Folk Society's monthly bashes at the Fringe Club. But it does feel like a lost opportunity for it not to broaden its appeal. Folk music is not just a British-Irish domain. Hong Kong may still be a British colony, but it is also one of the most cosmopolitan cities in the world. Why therefore should the Folk Festival not include music from other cultures? Folk after all is nowadays frequently called ''roots'', ''traditional'' or ''world'' music. It was the marketing creation of the '80s, and is proving remarkably successful at attracting audiences to listen to new and traditional music from all over the world. The WOMAD (World of Music and Dance) organisation, brainchild of Peter Gabriel, recently set up its first tour of the US. The line-up featured an enormously broad spectrum of music - hip-hop, rock and other pop genres as well as Indian, African, South American and Chinese musicians. Their final show at San Francisco's Golden Gate Park drew 250,000, the biggest concert in the US this year. Progressive musicians are continually breaking down barriers, and celebrat- ing music's wealth and variety, rather than fiercely guarding their own ghettos. Rock's current trend for acoustic music shows a folk edge. This summer's Cambridge Folk Festival in England, one of the more conservative festivals, featured bands such as Green on Red and The Rockingbirds, who appeal as much to rock audiences as folkies, alongside Christie Moore, Cajun music and blues. Look also at the popularity of singers such as Tracey Chapman, Suzanne Vega and Billy Bragg, all of whom have strong folk roots. Of course, the festival works on a small budget, and the fact it has been able to import so many artists should be applauded, but why not look to some of the cultures more local to Hong Kong? There is a varied and popular musical culture in the Philippines (surely some of the Filipino bands in Hong Kong play traditional music) and why not include some Chinese performers? How about the guys who busk near the Star Ferry playing South American music? There may be some of the old guard who quake at the thought, but you can't please everyone, especially traditionalists. Remember those who abused Bob Dylan when he went electric. Hong Kong's cosmopolitan feel should be celebrated, and folk music, with its emphasis on roots and culture is an ideal way to do so. Perhaps next year we may see the first Hong Kong World Music festival.