Growth has been driven by the World Cup, warm weather and summer sales, according to the CBI. Sectors performing particularly well were clothing, groceries and footwear and leather.
The CBI Distributive Trades Survey found that 51% of retailers had seen sales rise during the period 23 June to 14 July, while 18% had seen a fall, giving a balance of +33%.
This was considerable ahead of the forecast figure of +11% and was the highest balance since April 2007, when the figure was =44%.
Even more growth is being forecast for August, when the CBI expects the balance to be +45%, which would be the highest figure for over six years.
The CBI warned, however, that it was not a sign of a return to boom.
Lai Wah Co, head of economic analysis at CBI, said: "We still expect the recovery in overall consumer spending to be fairly restrained, however, given concerns about the impact of public spending cuts and weak prospects for real take-home pay in the coming year."