Aldi, Asda. Tesco and Lidl are among the cheapest supermarkets in the UK

The experts at Which? published their latest monthly analysis in August, showing that Aldi was the cheapest supermarket for a regular store, while Waitrose was the most expensive.

Every month Which? Compare prices on 37 popular grocery items, including potatoes, chicken and milk, at major UK supermarkets.

In August they found that Aldi was the cheapest at £65.21, beating rival Lidl by just £1.32.

Aldi, Lidl, Tesco and Asda were named the cheapest supermarkets in August (Image: Which one?)

The same basket at Waitrose cost £79.51, a 22% increase compared to Aldi.

Asda was the one cheapest of the “big four” supermarkets to Which?, followed by Tesco, Sainsbury’s and then Morrisons.

Which? said: “Our basket of 37 items included Albert Bartlett Rooster potatoes, private label chicken thighs and whole milk.

“Aldi was the cheapest supermarket overall in August: our store cost £65.21, which was £1.32 ahead of its discount rival Lidl.

“The same basket at Waitrose would have cost you an average of £79.51 – that’s an average of 22% more expensive than Aldi.”

“For the Big Four supermarkets, our comparison showed that Asda was the best cheapest for our shopping cartfor £71.48.

“We look at the prices of hundreds of groceries across eight major supermarkets every day throughout the month using an independent price comparison website.

“For each supermarket, we calculate the average price of each item over the course of the month before adding them together to get each store’s average price for our basket and cart of products.

“For fairness, we consider special offers but do not include multiple purchases or loyalty program discounts in our analysis.”

The news comes as the Bank of England has warned Food prices would remain high for the rest of the year.

The bank said there was “fairly broad agreement” that food price inflation had now peaked and was expected to be significantly lower, “perhaps around 10% or slightly lower” by the end of the year.

It said cost inflation among food producers had declined but still remained much higher than usual and it could take longer for some producers to feel reduced pressure, particularly if there were annual contracts with suppliers or group purchasing arrangements.

Many food producers were also exposed to considerable cost pressure from wages and energy.

Which? Sue Davies, head of food policy, said: “It is worrying that food prices are expected to remain high for the rest of the year as people continue to struggle.

“That means they will continue to put enormous pressure on millions of families and low-income people who are struggling with rising costs month after month.

“Supermarkets can take sensible steps to help customers who rely on more expensive convenience stores by ensuring they stock a range of well-priced products that support a healthy diet, such as Which? Research has shown that these items are rarely, if ever, available for sale in smaller stores.

“The Competition and Markets Authority recently approved Which? Food prices can be unclear, so supermarkets must also act immediately to make it easier for shoppers to compare prices, while the Government must fulfill its promise to close the loopholes that make it too easy for supermarkets to confuse shoppers.”