SuperGroup, owner of the Superdry fashion brand, was dealt another blow on Tuesday when the co-founder of the business, Theo Karpathios, abruptly quit "to take on new challenges".

Photo: Corbis

In a statement the firm, whose celebrity fans include David Beckham, Pippa Middleton, Ed Sheeran and Tulisa Contostavlos, said Karpathios had tendered his resignation and will step down from the board immediately.

Karpathios, who owns a 14.8 percent stake in SuperGroup, had been with the business since 2005 and held the position of chief executive officer, wholesale and international.

The firm said a process to find his successor was underway.

A spokeswoman for SuperGroup said he departed on good terms and denied he had rowed with Chief Executive Julian Dunkerton.

SuperGroup was one of 2010's most successful stock market flotations. After listing at 500 pence its shares rocketed to a high of 1,899 pence in early 2011. But three profit warnings and a litany of management mistakes have led to a dramatic reverse.

Shares in the firm closed Monday at 434.5 pence, valuing the business at 349 million pounds ($548 million).