Harriet Walker: The label will lose its cool if it continues to chase ubiquity

If fashion relies on cheques and balances, then Supergroup may well have tipped the scales. The recipe for cool is notoriously elusive, and the industry's alchemists spend thousands of hours and pounds trying to decant it, but it doesn't take much for a successful company to come tumbling down.

The swift rise of the streetwear label Superdry was something of a phenomenon – serving faithful customers with offbeat tastes since 1985, it suddenly became a motif and aspirational must-have for the trend-savvy teenage and youth markets.

You might think that catering to a broader market and becoming more conspicuous can only be beneficial. Wrong. In fashion – and in the currency of cool – ubiquity is death. In this economic climate, brands must patrol their identities fiercely – one whiff from those who make tastes that a logo or style might be "over", and it's time to pull down the shutters.

The great danger for Superdry is to forget its roots and to alienate the customers who bought it when it was sold in skate shops and other sub-cultural outlets. It is not a brand which naturally strides the avenues of Westfield and other such malls, and the new customers it picked up on its ascent are famously flighty.

It has ever been thus when brands become too successful too exponentially. French Connection's FCUK phase is a case in point – its tongue-in-cheek slogan T-shirts were on everyone's shopping list for a while, but then became unutterably naff and the chain was forced to reappraise.

Superdry must try to lose its "of the moment-ness", which may seem counter-intuitive, but is crucial for any company in the fashion industry for the long haul.