Asos, the internet fashion retailer, defied the gloom pervading the high street, almost doubling sales over what it claimed was a "cracking" festive period.

The company, which targets internet-savvy 16 to 34-year-olds, said that it now expected pre-tax profits for the year to the end of March to be "signficantly ahead of market expectations".

Although high street retailers such as Next and Marks & Spencer have been finding the going tough, Asos said that it remained "bullish" over its prospects for the coming year.

It reported an 86 per cent jump in sales in the seven weeks to January 20, with turnover for the first 42 weeks of its financial year up 88 per cent on last year.

The company, which offers more than 6,500 lines ranging from clothing to footwear and accessories, said that it had 1.7 million registered users.

The most popular products over Christmas included a £35 satin bow shift dress styled on outfits worn by Victoria Beckham and a “prom” dress akin to those worn by the American socialite Paris Hilton.

There were fears that some internet shoppers could be disappointed by a postal system struggling to cope with the boom in online orders, but Asos insisted that it had experienced “no major delivery issues” in the build-up to Christmas.

Nick Robertson, the chief executive, said: "We had a cracking Christmas. Sales were ahead of internal forecasts, margins remained strong and stock positions healthy."

He said that he was confident of the group's ability to ride out a consumer downturn.

“If there is a spending squeeze, for a business growing at this sort of rate we can afford to lose 10 per cent of sales," he said.

"I’m full of confidence and very bullish about the year ahead.”

Analysts pushed their full-year profit forecasts up from £5.7 million to about £6.7 million.

Asos, which sells 135 designer brands in addition to its eponymous brand, was founded in 2000 and floated on AIM the following year.

The company has kept up a rapid growth rate since flotation, overcoming the impact of the Buncefield oil depot fire in December 2005, which damaged stock at its warehouse in Hemel Hempstead, Hertfordshire.

Shares of Asos, which have doubled since September, added a further 15.5p to 242.5p in early trading.

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