Sales at department store chain John Lewis rose 14.9% in the first half, or 12.6% excluding VAT.

However managing director Andy Street cautioned that the rate of growth is unlikely to be sustained.

Street said: “Looking ahead, our first half-year’s form should give us great confidence for the all-important second half. But we should be realistic in our expectations as we come up against stronger figures from last year. I suspect we won’t finish with another 15% advance.”

Compared with the comparable pre-recession period in 2008, turnover was 11.4% ahead. “These results show us winning market share in each of our buying groups – fashion, home and electricals and home technology,” said Street.

Fashion sales climbed 19% in the half, home rose 16.7% and electricals and home technology “prospered” as the World Cup helped TV sales. sales surged 36%.

The first-half sales total accompanied John Lewis’s usual weekly update. The retailer reported a sales rise of 5.3% to £52.7m in the week to July 31. Fashion sales rose 9.4%, home was up 5.8% and electricals and home technology down 1.2%.

Stablemate grocery chain Waitrose posted a 9.3% rise in sales last week to £90.4m. Retail director Tony Solomons said warm weather food, such as prepared salads, sold well.