Which? has revealed how supermarket grocery prices compared from shop to shop last month. Every month, the consumer champion compares thousands of prices at the UK’s eight biggest supermarkets – Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose – to reveal the cheapest place to buy your groceries and household essentials.

Which? compares a small basket of items at shops including Aldi and Lidl with retail giants including Tesco and Asda to see where you money will go the furthest. The comparison includes 37 everyday items and groceries each month.

This month, Aldi was the cheapest supermarket in August overall, with the shop costing £65.21, pipping its discounter rival Lidl to the post by £1.32. The same basket of items at Waitrose would have set you back an average of £79.51, that’s 22% pricier on average than Aldi.

When it came to the ‘big four’ supermarkets, our comparison revealed that Asda was the cheapest for the basket at £71.48. Waitrose came out as the most expensive, and was £43.69 pricier than Asda on average, with a big shop typically costing £369.04.

Average shopping basket price by supermarket

Aldi - £65.21

Lidl - £66.53

Asda - £71.48

Tesco - £74.00

Sainsbury’s - £74.12

Morrisons - £75.37

Ocado - £79.38

Waitrose - £79.51

To work out the prices, Which? tracks the cost of up to 200 branded and own-label products every day over the course of a month to work out the average cost per item. The averages are then added up to get a total for each retailer.

The contents may vary from month to month and might include anything from Andrex toilet paper and Lurpak butter to own-label bread and Heinz baked beans.