Which?’s monthly analysis involves comparing the average prices of popular groceries at eight of the UK’s biggest supermarkets. Experts also look at a larger trolley of groceries at six supermarkets, as the discounters do not always stock big-brand products.

The cheapest supermarket for a smaller basket of goods this month was Aldi, coming in at £65.21 on average across the month. Fellow discounter Lidl was just behind Aldi, with a difference of £1.32 (£66.53 on average).

Waitrose was the most expensive this month, with a basket of groceries totalling £79.51 on average, which is 22% more than Aldi – a difference of £14.30.

Which? also compared the cost of a larger trolley of 133 items – the original 37, plus 96 more. These included a larger number of branded items, such as Andrex toilet paper and Cathedral City cheese, and did not include discounter supermarkets Aldi and Lidl, as they do not always stock some of these products.

In August 2023, it cost £325.35 on average for this shop at Asda, beating the next cheapest, Morrisons (£341.28), by £15.93.

Waitrose was £43.69 more expensive than Asda, coming in at £369.04 or 13% more, on average, for the trolley of comparable goods.

Calls for more support for shoppers

This latest pricing analysis from Which? demonstrates that shoppers can make considerable savings on their groceries depending on where they buy their food. However, even budget ranges at the discounters have risen in price significantly, and with most of the traditional supermarkets’ convenience stores failing to offer or stock budget lines, the consumer champion believes supermarkets must do more to help their customers.

Which? has found that while some good practice exists, many of the major supermarkets have not done enough to support their customers during the cost-of-living crisis.

The group said that supermarkets could be doing more by ensuring smaller convenience stores stock a range of essential budget lines that support a healthy diet, especially in areas where they are most needed. Morrisons recently led by example by committing to stocking 40 of its budget items in its smaller convenience stores in the coming weeks.

Which? said supermarkets also need to ensure unit pricing is clear so that customers can easily work out the best value products. This includes providing unit pricing on loyalty card prices.

Ele Clark, Which? retail editor, said: “The cost-of-living crisis is taking its toll on households up and down the country and with many turning to discounters for their food shop, it is no surprise that our latest research shows that once again Aldi is the cheapest supermarket.

“Which? believes that supermarkets are failing to adequately help shoppers during the current crisis. They must ensure everyone has easy access to basic, affordable food ranges at a store near them – including providing a range of essential budget lines that support a healthy diet in smaller convenience stores. They must also provide transparent and comparable pricing so people can easily work out which products offer the best value.”

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