Shoppers loyal to big-name groceries are being urged to watch where they buy after new research found price gaps of up to 17% across the major supermarkets.
Analysis by consumer group Which? shows Asda was the cheapest place to buy branded goods for the third month running in April, with rivals trailing behind, particularly for those not using loyalty cards. The watchdog tracked 240 popular branded items - from Heinz baked beans to Nescafé coffee - and found Asda's basket came in at £795.21 on average.
By contrast, Sainsbury's without a Nectar card was the most expensive at £933.57 - a hefty 17% more. Even premium chains such as Waitrose (12.58% more) and Ocado (9.57% more) undercut some rivals when loyalty discounts were not used.
Loyalty Pricing Reshaping Supermarket Bills
The findings underline how loyalty pricing is reshaping supermarket bills, with Tesco and Morrisons offering significantly lower prices for members. Without a Clubcard, Tesco shoppers paid around 15% more than Asda, showing how failing to scan a loyalty card can significantly inflate the cost of a shop.
The research also revealed striking price swings on everyday items. Colgate Plax Cool Mint Mouthwash was 125% more expensive at its priciest supermarket than its cheapest, while Listerine mouthwash was up to 124% higher. Staples such as rice (+115%), cakes (+101%) and shampoo (+100%) also saw major price differences depending on where shoppers bought them.
Impact on Shoppers Without Loyalty Cards
Crucially, Which? warned that not everyone can or wants to sign up for loyalty schemes — meaning some households may be disproportionately hit by higher prices. Tesco currently restricts Clubcard access for under-18s, although it has said it will review the policy. Meanwhile, Asda and Ocado do not use member-only pricing, meaning all shoppers pay the same price regardless.
A Sainsbury's spokesperson said the examples highlighted were cheaper with Nectar prices, adding that 85% of its sales involve a loyalty card. Morrisons said it remains "committed to providing good, honest value", while Waitrose said the comparison was only a snapshot and did not reflect all promotions.
Which? said the figures show shoppers sticking to branded goods could be paying a significant premium - particularly if they fail to take advantage of loyalty discounts.
