John Lewis sales dropped last week as the hot weather drove consumers away from shops during a “challenging” period of trading.

The department store group said sales dipped 2.3% to £71.4m during the seven days ending August 13 as the sun shone on most of the UK.

Footfall dropped as shoppers opted to enjoy the weather on days out and head abroad on holiday.

But John Lewis said the latter trend drove a 17.8% uplift in sales at its store in Heathrow.

John Lewis posted a 2.6% slump in fashion sales compared with the same week last year, although the sunny spell boosted sales of warm weather lines, which rose 6%.

Sunglasses jumped 21% and sandals, which increased 14%, was the standout performer in that category.

Team GB’s success in the Rio 2016 Olympics helped sports sales grow 9.4%.

Electricals and home technology also suffered a fall in sales, down 2.2% on the year.

Strong sales in headphones drove audio sales up 6.7%, but cooling appliances were the best-performing category as sales spiked 54%.

John Lewis’s home division also endured a “difficult” week, as sales declined 1.4% despite furniture growing 4.2%.

Waitrose boost

By contrast, the department store chain’s sister retailer Waitrose benefited from the heatwave, as total sales advanced 1.1% to £122.69m.

Ranges suited to hot weather proved particularly popular at the upmarket grocer, as sales of rose wine and beers grew 26% and 16% respectively.

Waitrose shoppers appeared to favour cooking outside as they took advantage of the weather by hosting barbecues.

Sales of barbecue coal and fuel jumped 32%, while barbecue meats and burger buns advanced 20%. Salads and corn on the cobs rose 10% and 6% respectively.

Outdoor dining ranges, including plastic plates and glasses, jumped 38%, while shoppers also stocked up on summery desserts as ice cream sales grew 17%.