A mystery shopper test by consumer group Which? has ranked UK supermarkets on their food freshness. Tesco came out on top, with food lasting a whopping 11 days, but Waitrose was bottom of the list, with food only lasting 8.6 days on average.

This was based on the use-by date, rather than the best-before date. A group of mystery shoppers ordered 1,000 food items from six of the most popular British supermarkets. Each of the mystery shoppers had to order the same items, total up and find the average of days between the food arriving and the use-by date.

Sainsbury's, Asda and Morrisons all delivered one item each that went out of date on the day of delivery. Sainsburys, Morrisons and Waitrose delivered a few food items that became unsafe to eat the day after delivery.

Some food within use-by date had gone off before the date. Minced beef from Waitrose, Ocado and Asda had expanded with air, with the Waitrose minced beef turning grey. A salad from Ocado turned soggy before the use-by date.

The packaging of ten on the items may not have been safe to eat as it arrived very damaged.

Sainsbury's, Ocado and Waitrose delivered leaking milk and cream, Morrisons delivered bacon in split packaging and Ocado delivered a broken pasta salad.

Tesco and Asda had no damaged packaging.

Asda came out second on the list, averaging 10.5 days of freshness. Ocado came up behind Asda, with a shelf life of 10.4 days on average.

A Waitrose spokesperson said: "We always train our partners to pick products with the longest best-before date for online deliveries. We're sorry this fell short of our high standards and are committed to making this better for our customers.

"From time to time we sometimes shorten the date codes on certain fresh produce to ensure it's at optimum quality, so this may also have been a factor behind the results."

A Sainsbury's spokesperson said: "Our groceries online customers receive products with the longest possible shelf life and our colleagues receive training to ensure they select the freshest items available. If a shorter shelf-life product is due to be included in a customer's order we will email to let them know in advance and they have the option of returning it to the driver for a full refund."