Discount supermarket Aldi was ranked the lowest priced supermarket in the UK for seven consecutive months, from June to December, while Lidl was the cheapest for five months, from January to May.
Which? compared the prices of 48 popular groceries in December and found the cost of a basket of items was £81.63 on average at Aldi - £1.61 cheaper than its closest rival.
Lidl came in second at £83.24 on average, followed by Tesco in third place at £93.42, Asda in fourth at £93.44, Sainsbury’s in fifth at £95.71 and Morrisons in sixth at £97.12.
Ocado shoppers paid £102.87 on average, while Waitrose was the most expensive shop at £112.62 - more than £30 pricier than Aldi.
As for a bigger shop Which? compared a trolley of 149 branded items. As branded items are not always available at Aldi and Lidl, the two supermarkets were excluded from this comparison.
In this ranking, Asda was the cheapest of the traditional supermarkets in December - as it has been every month for the last three years - at an average cost of £355.62.
Sainsbury’s was the second cheapest at £368.97, followed by Tesco at £375.97, Morrisons at £377.81 and Ocado at £386.68.
Waitrose was again found to be the most expensive place to shop, with the trolley of items coming to £406.95, £51.33 more than Asda.
Reena Sewraz, Which? retail editor said: “With food and drink prices putting huge pressure on household budgets, it’s no surprise to see many people turning to discounters like Aldi and Lidl when our research shows they could save up to £31 on a typical shop.
“As well as choosing a supermarket that is cheap overall, you can save in other ways by swapping from branded to cheaper own-brand products and by sticking to a shopping list.”
“Which? believes all supermarkets have the ability to make a real difference to hard-hit households by ensuring everyone has easy access to basic, affordable food lines at a store near them, particularly in areas where people are most in need.”
The rankings in full
Listed are the cheapest UK supermarkets for a basket of 48 items, according to Which?:
- Aldi - £81.63
- Lidl - £83.24
- Tesco - £93.42
- Asda - £93.44
- Sainsbury’s - £95.71
- Morrisons - £97.12
- Ocado - £102.87
- Waitrose - £112.63
Listed are the cheapest UK supermarkets for a trolley of 149 items, according to Which?:
- Asda - £355.62
- Sainsbury’s - £368.97
- Tesco - £375.97
- Morrisons - £377.81
- Ocado - £386.68
- Waitrose - £406.95