Soaring temperatures boosted sales of food, alcohol and clothing in July to fuel hopes over the recovery in consumer spending.
Retail sales rose 1.1% in July on a month earlier and were up 3% on July 2012 - the steepest rise for two and a half years - driven by soaring sales at supermarkets and department stores.
The heatwave saw shoppers stock up on barbecue goods to drive food sales volumes 2.1% higher on a year earlier, the sharpest rise in more than two years, figures from the Office for National Statistics (ONS) showed.
The 1.1% gain was well ahead of economists' average hopes for a 0.7% month-on-month increase and will add to hopes that overall third-quarter GDP growth can exceed the 0.6% gain seen in the April to June quarter.
It was the third consecutive rise in month-on-month retail sales, following June's 0.2% increase.
The figures suggest a likely boost from the birth of Prince George and British sporting success, including Andy Murray's Wimbledon victory, Lions rugby, and Ashes cricket.
Department stores saw July sales surge 3.1% on a year earlier, while sales of textiles, clothing and footwear were up 1.4%.
Supermarkets also reported higher sales of garden furniture, although household goods stores were a rare weak spot, with sales falling 2.3% on a year earlier.
Month on month, there were dips in sales volumes across department stores and textile, clothing and footwear retailers, but supermarket sales grew 2.5%.