John Lewis Partnership sales leapt off the back of a washout bank holiday weekend, the school half term and a promotional push.
The employee-owned department store hailed a "really good sales week" in the seven days to May 31 with total sales up 8.5% over the year. This was driven by a 16.8% jump in department stores sales, while its food stores under the Waitrose brand were 3.7% up.
"Shops had a particularly good week, clearly making the most of the additional footfall," said the firm.
John Lewis has 91,000 permanent staff across 42 department stores and 318 supermarkets. They are defined as "partners" in the business.
Employees have a say in the firm's running through a democratic committee structure and share in the profits with an annual bonus. In 2014, staff received a bonus worth 15% of their annual salary.
The company is planning to almost double the number of its stores and increase its international presence.
John Lewis wants 65 stores by 2023. In addition, it will also be starting an e-commerce website in French and plans an international store in the coming decade.