When our mystery shopper visited Asda's Handsworth Road store in Sheffield, the store was clean, well-merchandised, the staff friendly and she had her shopping packed without asking. She said that she had a "thoroughly enjoyable experience" at the store, which won this week's Top Store award.

On this form, the company may struggle to justify the new self-service tills, which the store said would be installed soon.

The Tesco store in South Queensferry, Lothian was also clean and free of clutter, although our shopper was unable to pick up the Mach3 Turbo razor, which was out of stock.

The Sainsbury on Cuerden Way in Bamber Bridge, Preston was clean and well-presented. However our shopper noted that lemonade, which was bulked out into the aisle to increase available stock, was obstructing shoppers' movements. She also felt that staff could have been quicker to open tills as queues developed.

Our mystery shopper in Highbridge, Somerset found that the Somerfield store was well-merchandised and clean, but it was slightly cluttered with trolleys and shelf stackers.

Our Waitrose shopper in Portishead was disappointed. The store was poorly stocked and many spaces on the promotional gondola ends were empty. She also noted that the staff were spending time handing out leaflets rather than restocking shelves.