Every month Which? compares how much the UK’s biggest supermarkets charge for a trolley of groceries.
There’s regularly a price war between Aldi and Lidl.
Lidl was crowned the UK’s cheapest supermarket in February narrowly beating rival discounter Aldi.
The consumer group Which? tracks the prices 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.
Those averages are then added up to get a trolley total for each retailer.
Which? compared the price of 19 essential items and on average found shoppers paid £19.13 at Lidl for a trolley of groceries, 25p less than at Aldi.
Asda was the third cheapest supermarket.
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The big shop included a greater selection of branded items and own-label products.
The big four supermarkets Tesco, Sainsbury’s, Asda and Morrisons – plus Waitrose and Ocado were compared.
Asda claimed the top spot charging customers £160.89 for 85 items.
Waitrose was the most expensive supermarket at £178.79.
Grocery prices at Sainsbury’s, Morrisons and Tesco were similar, with just over £4 separating the three supermarkets.