Ocado grew sales by 10% week-on-week after it introduced a controversial policy of price-matching Tesco on more than 5,000 branded products, it claimed.

Chief financial officer Jason Gissing said sales had increased from £7m to £7.7m in the first week of May. He attributed the increase to the new pricing policy and the end of the Easter holidays, which reduced the influence of seasonal promotions on the market.

"We grew over 10% in a single week," said Gissing. "That is more than most retailers will grow in the whole of 2008. Our customers are clearly loving the strategy."

The Advertising Standards Authority is currently investigating a complaint by Tesco that Ocado's price-matching claims are misleading. Ocado recently said it would consider filing its own complaint against Tesco because its price comparison website pitched own-brand Tesco products against own-brand Waitrose products, a comparison Ocado said was invalid.