Among the biggest sellers was a £35 satin bow shift dress styled on outfits worn by Victoria Beckham, while its £75 "Prom" dress similar to those worn by the heiress Paris Hilton also proved popular.

Nick Robertson, its chief executive, said annual pre-tax profits are expected to come in ahead of the £5.9m expected by the market after "a cracking Christmas". Although many high street fashion retailers, including Marks & Spencer and Next, have reported weak trading over the festive period, internet retailers have performed better.

Mr Robertson said 40 per cent of the company's profits are generated at the end of the year as its customers search for party dresses.

Despite concerns of a consumer slowdown, he remains bullish on the group's prospects.

Asos, which stands for As Seen on Screen, has 1.7 million registered users and targets the 16-to-34 age range, with clothing based on celebrity outfits.

There had been concerns that many internet shoppers would be disappointed by a postal system struggling to cope with the sheer volume of online orders, but the company said it saw no major delivery issues in the run-up to Christmas.

Andrew Wade, at Seymour Pierce, said: "Despite the pressure on the consumer, we have no doubt that Asos will continue to benefit from both favourable macro trends and the many growth opportunities that are available to the business now it has taken a clear lead in the online fashion retail space. Certainly at the current levels, we would aggressively pick up stock and we reiterate our recommendation of 'buy'."