company 's success has been put down to shoppers hunting bargains and taking sales away from britain 's four big supermarkets , asda , tesco , sainsburys and morrisons .
the budget retailer last week announced that sales exceed £ 1billion for the first time last year becoming europe 's largest single-price discount retailer .
the company 's success has been put down to 50 per cent more expensive than those sold in supermarkets .