According to the CBI, 51% of retail businesses said sales had risen in July, compared with 18% reporting sales down. This balance of 33% compares favourably with an overall -5% pattern in June, and is the highest since April 2007.
Economists had forecast a balance of just 3%, with retailers expecting 11%. The most significant growth came in grocery, clothing and footwear.
The fact that sales of food, drink and televisions rose markedly during the period indicates that the World Cup had a significant effect on growth.
Retailers are the most optimistic they have been for six years about trading prospects. A balance of 45% are expecting to reach higher sales volumes in August.
However, they were warned against being over-optimistic. Vicky Redwood, of Capital Economics said: "We remain sure that the fiscal squeeze will slow the economic recovery eventually."