A new survey from consumer champion Which? that tracked the cost of shopping at your convenience store compared to a large supermarket has found that shoppers could be spending more than £800 a year extra.

Which? compared the prices of store-label and big-brand items at Tesco Express and Sainsbury’s Local against the prices of the same items online or at the companies’ big stores.

The comparison found that 75 items at Tesco Express, such as Anchor Spreadable Butter, a loaf of Hovis white bread and Tesco-brand milk, cost an average of £15.73 more on a weekly basis than if the items were purchased at a big Tesco. That comes to a convenience penalty of £817.91 when factored over a whole year.

The shoppers suffering the most, Which? said, were people with poor access to online delivery or those living in neighbourhoods without a larger supermarket. (There are nearly 50,000 convenience stores across the UK, according to Which?.)

Pressure on households

Sue Davies, Which? head of food policy, said: “Convenience stores offer a local lifeline for some shoppers, but Which? research shows shopping at a supermarket convenience shop rather than a bigger store comes at a cost – at a time when soaring grocery prices are putting huge pressure on household budgets.”

Conceding the constant fluctuation in prices, Which? found sharply higher price tags at both Tesco Express and Sainsbury’s Local after checking the costs each week of 2022. 

A shopping list of 69 items – including McVities biscuits, Birds Eye Potato Waffles and Heinz tomato soup, rang up £477.93 higher over a year if bought at a Sainsbury’s Local instead of online or at a bigger store. 

The biggest supermarket shocks

One of the more staggering differences (37%) was spotted on own-label sweet potatoes: 95p on average online or at a big Tesco but £1.30 at Tesco Express.

Meanwhile, Mr Kipling Bakewell slices were £1.27 online or at larger stores, but £1.62 at Tesco Express – a premium of 28%.

The biggest difference spotted at Sainsbury’s was Heinz cream of tomato soup. It was £1.37 at Sainsbury’s Local, 19% more expensive than the £1.15 price online and at the bigger store. 

Interestingly, not everything was more expensive at convenience stores. Which? said the prices of Anchor Spreadable Butter Tub (500g), Colgate Total Original Toothpaste (125ml) and Magnum Almond Ice Cream (4 pack) were all 3% lower on average at Sainsbury’s Local than at a bigger Sainsbury’s or online. It also found a block of Tesco’s own-brand unsalted butter was 2% less on average at Tesco Express than online or at bigger Tescos.

Call for action

Which? is asking big chains to ensure they stock budget ranges and make their unit pricing clearer, more legible and consistent so shoppers can identify the best deals.

Davis said: “We know the big supermarkets have the ability to take action and make a real difference to people struggling through the worst cost-of-living crisis in decades. That’s why we’re calling on them to ensure everyone has easy access to basic, affordable food lines at a store near them, can easily compare the price of products to get the best value and that promotions are targeted at supporting people most in need.”

Which? said Tesco would not comment on the research. A Sainsbury’s spokesperson said: “There may be price differences between convenience stores and supermarkets. This is because our Sainsbury’s Local stores are located in city or town centre locations and their operating costs, for example rent and rates, are higher.”