Excluding fuel, total sales at Waitrose were up 8.2 per cent on last year. The retailer said both the good weather and generous promotions were responsible for the sales lift - barbeque product sales were up by 69 per cent.
At John Lewis however, sales fell to £78.9m, down 3.5 per cent year-on-year.
Fashion was hit hardest, with sales falling 9.9 per cent on the same week last year, but furniture proved popular - up by 11.2 per cent year-on-year.
"The start of the new school year falling later this year means that parents and children are likely to be shopping for school uniform in the current week as the new term begins," said Jon Williams, director of John Lewis' merchandising operations.
Waitrose's personnel director Helen Hyde said: "As customers kept cool, ice lollies saw an uplift of 108 per cent with hand held ice creams up 100 per cent.
"Rosé wine and gin were among the most popular tipples seeing sales rise by 65 and 36 per cent respectively. Customers were clearly enjoying time in their gardens as outdoor plant sales blossomed by 11 per cent."
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