Sales at the employee-owned retailer's 26 UK department stores increased 13.1 per cent to£48.12 million.
John Lewis customer service director Simon Fowler said: 'Cooler weather, a bank holiday and a good deal of earnest preparation for back to school resulted in increased footfall and a really strong outcome.'
The electricals and home technology category outstripped all other selling directives, with a 26.9 per cent sales increase. Furniture and textiles also performed well, with a 14.4 per cent rise in sales.
Sales at the group's chain of 180 Waitrose stores were up 9.8 per cent to£68.1 million, lifted by the build up to the bank holiday weekend. Despite the uplift, Waitrose supply chain director Tony Solomons said: 'The cooler weather contributed to a relatively modest week's trade.'
Total sales at the group increased 11.2 per cent to£116. 6 million.