John Lewis sales slowed on last year as the good weather resulted in a drop in footfall for the week to September 8.

Sales increased by 4.3%, compared with 10.4% the previous year, totalling £64.3m.

Despite this the department store group recorded a good week-on-week increase in London 2012 merchandise, driven by the final week of the Paralympic Games, while the retailer’s own Celebrate Britain range was popular.

John Lewis said the launch of the Alice Temperley Somerset range “far exceeded expectations” and it said sales of its back-to-school range jumped 12% year on year, posting a 10% increase in schoolwear.

Electricals also advanced 16%, led by communication technology and supported by white goods, with laundry up 17%. John Lewis revealed it will be unveiling new products in the coming weeks.

Sales at its sister company Waitrose increased 8.4% to £108.2m as the grocer said shoppers used the warm weather to entertain family and friends.

Charcoal sales soared 554% as people fired up the barbecue and meats were up 115%. Mediterranean style foods were popular – halloumi sales surged 75%, feta jumped 43% and mozzarella increased 29% on last year. Asparagus and new potatoes advanced 65% and 35% respectively.

Ice cubes and ice creams increased 82% and 125% respectively and ice lollies surged 120%.

Picnic items were also up, as quiche sales increased 35% and its range of sandwiches, salads and snacks rose 25%.

Suncare rocketed 144% in the week as shoppers “prepared to spend time outdoors enjoying the late summer sunshine”.

Despite the warm weather, shoppers continued to buy ready meals with sales up 11%.

Waitrose posted a 35% increase across bagged apples as it introduced new season varieties.

Yesterday the John Lewis Partnership posted a 60% surge in profit to £144.5m in the half year to July 28.