If Christopher Kane and his big sister Tammy hadn't had a bad babysitter in the eighties, their Spring collection might have looked very different. "It was the pair of us sitting on the sofa watching late-night horror films like Carrie," said Kane. "And Crocodile Dundee." The two movies set him off thinking about chiffon and eerie suspended ruffles on the one hand, washed-out denim and snakeskin vests on the other. Then he bought a camouflage T-shirt on Dalston market. And because it was summer, Tammy was working in a giant £5 T-shirt dress from Primark. And so it went.

All these domestic details are material to the development of one of the most-watched young designers in the world. The Kane siblings work so closely their thought processes are virtually indivisible, to the point that the models in the show with their long, straight hair are dopplegängers for Tammy. Together, the duo can reinforce an odd combination of ideas until they walk the line between trashy and internationally elegant. One slip, though, and it'd be over.

This time, the snakeskin prints, western shirts, and stonewashed denims flirted with what Christopher calls the "dodge" side, but it was the loosened, floaty nature of the silhouettes that caused more surprise. Instead of thigh-grazing, body-gripping shapes, there were flyaway chiffon ruffles, some in Christopher's camouflage print, as well as slouchy T-shirting pieces developed from Tammy's work dress. After many reiterations that included a beautiful long white dress with ruffles banded in snake, their casual-western-romantic message had fully registered. As the VIP audience left the building, the noise of discussion was deafening: Is this collection a watershed in the mood of fashion? Will Kane confuse customers by moving on so quickly, or is he smart to outpace his copyists? Will the chiffon mills of Italy go into overdrive overnight? Quite possibly, the answer to all these questions is yes.