In a survey of the country’s supermarket, consumer group Which? found that for a basket of goods, Aldi shoppers saved £18 compared to the most expensive food store in the study, Waitrose.

This marks the German discounter as the cheapest supermarket for 12 consecutive months.

The Which? monthly analysis compares the average prices of a shop consisting of 40 popular groceries at eight of the UK’s biggest supermarkets.

A basket of goods bought at Aldi cost on average last month £68.60.

The seven remaining supermarkets’ basket of goods cost:

• Lidl £70.51
• Asda £76.45
• Sainsbury’s £77.13
• Tesco £77.56
• Morrisons £79.09
• Ocado £83.90
• Waitrose £86.91

Which? also compared the cost of a larger trolley of 131 items which included more branded items such as Andrex toilet paper and Cathedral City cheese, and does not include discounter supermarkets Aldi and Lidl as they do not always stock these products.

In May, Asda was once again the cheapest for the larger trolley of groceries, a title it has held since January 2020. In May 2023, it cost £332.40 on average for this shop, beating the next cheapest, Morrisons (£334.47), by just £2.07.

Waitrose was £31.59 more expensive than Asda at £363.99 on average for the trolley of comparable goods, 9.5% more.

Ele Clark, Which? retail editor, said: “The Which? Food Inflation Tracker shows that the price of food and drink is continuing to soar, as people suffer through the worst cost-of-living crisis in decades. It’s no surprise to see many shoppers turning to discounters like Aldi and Lidl when our research shows they could make savings of more than £18 on a basket of everyday groceries.

“Supermarkets aren’t currently doing enough to help shoppers. Which? believes the big retailers have a responsibility to ensure everyone has easy access to basic, affordable food ranges at a store near them, and to provide transparent and comparable pricing so people can easily work out which products offer the best value.”