Woolworths, Britain's biggest toy retailer, has sold 500,000 Beyblades in the last 10 days alone. The £5.99 Japanese tops are based on an ITV cartoon series and are designed to "fight" each other. The biggest challenge to parents is to find a Beyblades Stadium, an arena for the tops to spin in, of which there are said to be little more than a "handful" in this country.