Britain’s most affordable supermarket for branded goods has been revealed — retaining its top spot for the seventh consecutive month. Asda has been crowned the cheapest supermarket in August, even when stacked up against Tesco Clubcard and Sainsbury’s Nectar prices.

Research by Which? also revealed that shoppers can end up paying more than double for identical products depending on where they choose to shop and whether they hold a loyalty card.

Following an analysis of 220 popular branded groceries – including Heinz beans, Nescafé coffee and Mr Kipling cakes – the consumer watchdog found Asda was once again the most wallet-friendly supermarket overall, with the basket costing £771.21 on average throughout August, reports WalesOnline.

While Which? regularly identifies Aldi and Lidl as the cheapest supermarkets overall in its monthly price comparisons, neither features in this branded grocery analysis due to their insufficient range of branded products.

Tesco with a Clubcard (£782.39), Sainsbury’s with a Nectar card (£787.57) and Morrisons with More (£797.32) were the next most affordable options after Asda.

However, shoppers without loyalty cards faced considerably steeper costs, with Tesco (£860.29) and Sainsbury’s (£869.16) both proving pricier than Waitrose (£839.71) and Ocado (£815.28) on average, underscoring the dramatic impact loyalty pricing can have on branded grocery bills.

Shopping at Sainsbury’s without a Nectar card proved the most costly option overall, coming in at nearly 13 per cent more expensive than Asda.

Price of same product at different supermarkets varies by up to 114%

Consumer watchdog Which? also uncovered price discrepancies of up to 114 per cent across everyday household items at major supermarkets in August.

Listerine Total Care Clean Mint Antibacterial Mouthwash (500ml) continued to record the largest average price gap between supermarkets. The lowest average price was found at Sainsbury’s with a Nectar card (£2.80), while the highest was at both Sainsbury’s and Tesco without a loyalty card (£6) — a staggering 114 per cent difference.

Which? identified several other branded products — including Colgate Plax Cool Mint Mouthwash (500ml), Tilda Boil In Bag Basmati Rice (4 x 62.5g), Fox’s Chocolatey Milk Chocolate Biscuits Rounds (130g) and Vimto No Added Sugar Squash (1000ml) — priced at roughly double the amount at the most expensive supermarket compared with the cheapest.

During the period analysed, 149 products at Sainsbury’s were on loyalty promotion, alongside 143 at Tesco and six at Morrisons. None of the products examined by Which?

were subject to loyalty discounts at Waitrose, while Asda and Ocado do not operate member-only pricing in the same manner.

While loyalty cards can deliver considerable savings, some shoppers remain reluctant or unable to take advantage due to concerns over data privacy or eligibility criteria. Shoppers seeking the greatest savings might want to contemplate abandoning branded products entirely.

Which? consistently discovers that supermarket own-label options are substantially less expensive and frequently match the quality of prominent branded items.

Reena Sewraz, Which? retail editor, said: “With many households still facing intense financial strain, Asda has proved to be the most consistent for affordable branded goods. This month’s analysis also found that customers can pay more than double for identical products depending on where they shop and whether they use a loyalty card. To avoid paying more than you need to, shoppers should try to look out for promotions on branded items, compare value across different products, and check rival retailers to ensure they are getting a genuine deal.”

Which? examined the pricing of 220 groceries from the most popular brands – including Chicago Town, Dove, Kellogg’s, Mr Kipling, Nescafé and Tilda – daily throughout a month to calculate the average cost per item. These figures are totalled to establish each supermarket’s average overall price.

The selection represents the most popular brands spanning a broad range of grocery categories based on industry data and is intended to generate a reliable sample rather than to reflect a typical shopping basket. Which?

lists loyalty discounts separately in the table where applicable. The value of points, personalised discounts or other rewards are excluded as these vary between shoppers.

Every supermarket featured in the price analysis was given the opportunity to respond to specific examples highlighted by Which?

An Asda spokesperson said: “We’re proud that Which? has named Asda the lowest-priced supermarket for branded products for a seventh consecutive month. Others may talk about ‘unbeatable prices’, but independent research continues to show that Asda customers get the best prices on their favourite brands.”

A Morrisons spokesperson said: “Morrisons remains committed to providing good, honest value and that’s why we are guaranteeing ‘Unbeatable Prices’ on hundreds of weekly essentials.

“In addition, our More Card members can earn Five More Points on every product in store, online and in Morrisons Daily stores and also benefit from personalised offers and money-off coupons on the things they buy the most of. Customers to our Cafés can also take advantage of a range of offers such as our Kids Eat Free promotion, which runs every day, or free refills on all hot drinks.”

A Sainsbury’s spokesperson said: “We have not been able to verify the calculations used by Which? as the group has not shared its full analysis with us. With 85 per cent of sales involving a Nectar card, we’re confident our customers know they can get great value when they shop with us.

“We’re focused on offering outstanding value on the products people buy most often, with more than 10,000 Nectar Price offers available every week on top of personalised Your Nectar Prices.”

Tesco, Waitrose and Ocado did not provide comment.