FOR a sinking moment, it seemed William Tang had joined the crusade, then anxiety was swept aside. Ridiculous to even think that Hong Kong fashion's arch-iconoclast would follow the mob. Crosses, crosses everywhere. From Paris to New York, Christianity's symbol has become the season's hottest, most exploited accessory and frankly, the Vatican should be lodging protests. At least Tang can't be accused of sacrilege. Far from joining in the crass display, he has taken the spirit of the season and interpreted it in a way even the devout can applaud. The Nun's Fashion Story would serve admirably as the catch-line for much of Tang's Autumn-Winter '93 collection. As his models stepped out to the strains of Bach, their hair cropped or swinging loose in girlish innocence, the show took on a positively reverent air. The recent Hong Kong Fashion Designers Association annual show gave a glimpse of Tang's direction for winter when he presented a selection of Victorian-inspired gowns softened by quirky effects like newspaper pages inserted in the voluminous skirts. In fact it was mostly costume drama. As the full range revealed, Tang knows when to put the breaks on gimmickry. Ankle-length dress and coat combinations in black, grey, navy or white dominate. Most are cut to skim the body, with lean tops and gently flaring skirts, and the demure, yet sensuous silhouettes are accentuated by the fabrics. Cool wool, silk and crushed velvet are among Tang's favourites, making for a collection with almost equal appeal to the convent girl and the vamp. Pure-thinking types will adore Tang's pared-down dresses their white collars and cuffs, subtly contrasting underskirts or coats, and discreet fastenings. Just as you're murmuring Hallelujah, Wicked William pounces. Heavens, he's a naughty boy. Lace bras, hot pants and fishnet tights under sheer iridescent coat-dresses or Suzie Wong cheong sams. Coat and tails cut to reveal - well, more tails. Button-through dresses split outrageously high at the back. There are also copper mesh fantasies, ribbed tops that look like chainmail, variations of the little black dress - again the flared double skirt, but short and sassy - and best of all, stretch velvet bodysuits teamed with silky lace tops and big jacquard jackets. With a few exceptions most is wearable or at least adaptable, and looks comfortable. The Tang label, available at Seibu and the Trade Development Council's Design Gallery in the Hong Kong Convention and Exhibition Centre won't leave you broke either. ''My clothes start at $800 and $3,000 is the top price,'' William Tang assured after his show. Let's give thanks.