Up to £10 more sat on Tesco Clubcard prices in Which?'s July basket test when shoppers did not use the card. The gap came from loyalty-card pricing across a 93-product shop. For anyone buying a full basket without signing up, the bill can move by a double-digit amount on the same shop.
Tesco and Sainsbury in July
93 products formed the monthly test, and Tesco was still cheaper than Ocado and Waitrose in the ranking. Which? said a loyalty card can make a material difference in pricing at Tesco, even though Tesco and Sainsbury sat among the top five cheapest supermarkets in the July ranking, in that order after Asda.
£158.05 was Aldi's July basket average, leaving it the cheapest supermarket for the seventh month in a row. Lidl came next at £160.75, just £2.65 higher, while Waitrose averaged £226.95 and sat £68.90 above Aldi. Those gaps show how the ranking can separate a weekly shop by far more than a token amount.
In June and July
14.26 per cent was the size of Tesco's premium without a Clubcard versus Asda in June, and Which? said the same loyalty-card effect could lift monthly savings to five per cent. That leaves a practical split for shoppers: Tesco can look competitive in the ranking, then turn notably dearer when the card is missing at checkout.
Millions of shoppers were said in earlier research to be excluded from loyalty cards because they lacked digital access, did not have fixed UK addresses, or were aged under 18. For those customers, the price gap is not theoretical. It changes the cost of the same basket, and the only way around it is to use a Clubcard or shop where card pricing is not needed.
