By Kate Holton LONDON (Reuters) – British online fashion retailer ASOS ASOS.L warned full-year profits would miss forecasts by 30 percent as the strong pound forced it to cut prices in foreign markets, wiping 1.2 billion pounds ($2 billion) off its market value. Shares in ASOS, whose fast-changing fashions are a global hit with internet-savvy 20-somethings, were down 31 percent in early trading as it lowered its operating margin guidance for its current fiscal year, which ends in August, and for the next. ASOS, which stands for As Seen on Screen, was founded in 2000 by current chief executive Nick Robertson, and has grown rapidly as it met the demand for fast changing fashions. While sales in Britain have grown strongly, ASOS tends to make a lower margin in its home market.