Lidl has been named the cheapest supermarket for a basket of groceries - ending a 16-month run by rival Aldi.

A monthly comparison by Which? found a basket of 44 items came to £74.58 on average in October, just 17p cheaper than Aldi where the same items cost £74.75. Waitrose was once again the most expensive, with a basket of groceries coming to £91.15 - which makes it £16.57 more expensive than Lidl.

Which? also compared the cost of a larger trolley of 135 items – the original 44, plus 91 more. For the larger shop, Asda remained the cheapest supermarket, where it cost £328.42 on average. Waitrose was the priciest for the bigger shop as well, coming in at £378.08 - £49.66 more expensive than Asda.

Aldi and Lidl are never included in the larger shop comparison as they don’t always stock branded products. The analysis by Which? includes special offer prices but not multi-buys or loyalty discounts. Which? says it does not include loyalty prices as not every shopper is able to sign up to loyalty schemes.

Ele Clark, Which? Retail Editor, said Which? does not reveal the items used in its monthly comparisons so the results cannot be "skewered" by retailers. She said: “As millions continue to struggle with increased food prices and other high household bills, it is no surprise that many are turning to discounters for their food shop. Our latest research has found Lidl is the cheapest supermarket for a basket of groceries, narrowly beating Aldi.

“Which? believes that supermarkets can do much more to help shoppers during the current cost of living crisis. They must ensure everyone has easy access to basic, affordable food ranges at a store near them - and this includes providing a decent choice of budget-range, healthy essentials in smaller convenience stores.”

Which? is calling on supermarkets to ensure their smaller convenience stores stock a range of essential budget lines, as well as clearer labelling for unit prices.

Full results for basket of 44 items

  • Lidl - £74.58
  • Aldi - £74.75
  • Asda - £82.11
  • Tesco - £85.34
  • Sainsbury’s - £85.88
  • Morrisons - £86.35
  • Ocado - £90.37
  • Waitrose - £91.15

Full results for trolley of 135 items

  • Asda - £328.42
  • Morrisons - £339.40
  • Ocado - £354.54
  • Tesco - £358.08
  • Sainsbury’s - £364.61
  • Waitrose - £378.08