An equivalent basket of items at Aldi was found to be £25.68 cheaper than Waitrose. It was also £11.77 cheaper than Tesco and £13.62 cheaper than Sainsbury’s.

The news comes in the same week the discount supermarket teamed up with surplus food platform, Too Good To Go, to sell ‘Magic Bags’ costing £3.30 which contain £10 worth of groceries nearing their end date.

Tesco the cheapest of the ‘big four’

In a basket of 45 popular items, the cost at Aldi was £82.03 on average, £2.04 cheaper than Lidl.

The same shop at Waitrose cost £107.71 on average, almost £26 more than the discount supermarket. Of the ‘big four’ supermarkets, Tesco was the cheapest at £93.80.

To calculate which supermarket has the cheapest goods, Which? compared the following companies: Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose.

The group also compared the cost of a larger trolley of 144 items among the traditional big supermarkets. It found Asda to be the cheapest at £363.29, on average.

Sainsbury’s was the next at £375.84, followed by Tesco at £376.72. Waitrose was £45.43 more expensive than Asda, coming in at £408.72, on average.

Aldi was also awarded the title of cheapest supermarket of the year, for the second year in a row, for 2022 by the consumer group. Aldi was cheapest for seven months while Lidl held onto the spot for five. Across the seven months that Aldi was cheapest the average difference was £1.59 compared to Lidl.

Last week it was reported that grocery bills have risen by £800 in a year.

‘We are dedicated to keeping prices low’

Julie Ashfield, managing director of buying at Aldi, said: “We know just how important it is for families up and down the nation to find ways to cut costs anyway they can, and at Aldi we are dedicated to keeping prices low and quality high across all our products.

“The latest findings from Which? show that customers can save themselves over £25 on just one basket by choosing Aldi – that’s not just pocket change. The fact that Which? have found Aldi to be cheapest for eight months in a row is a testament to our commitment to our shoppers.”