The price of some of the most popular branded food products have as much as doubled in the last two years, research has found.

Heinz Tomato Ketchup saw the biggest average percentage increase overall, with its 460g top-down version increasing by 53% or 91p across six major supermarkets – although this reached 70% or £1.06 in one particular supermarket over the two-year period, according to a study by Which?

Dolmio Lasagne Sauce (470g) saw the second biggest average percentage increase of the 79 branded products in the watchdog’s survey, up 47% or 61p in two years and as much as 107% or £1.09 in one supermarket.

Which? compared the prices of the 79 items at Asda, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose over a 30-day period from September 21 to October 20 in both 2020 and 2022.

Heinz 400g Classic Cream of Chicken Soup also went up an average of 46% or 44p across the board from around £1 to almost £1.50.

Student staple Batchelors Super Noodles Bbq Beef Flavour (90g) went up an average of 43% across the six supermarkets from an average 59p to 82p.

Prices also increased on basics such as Hovis Granary Wholemeal 800g, up by an average of 43% or 58p, from £1.39 to £1.97.

One of the biggest price leaps was on branded butter, with a 500g tub of Anchor Spreadable up by £1.31 (45%) on average across all six supermarkets over the two-year period and a 500g tub of Lurpak Spreadable Slightly Salted increasing by £1.17 or 35%.

The price of Twinings Everyday 100 Tea Bags saw the sharpest individual increase at one supermarket, up by £2.33 or 64% in 2022 compared to the base price in 2020. Across the six retailers the teabags went up by an average 64p or 17%.

Which?’s findings suggest that the price of some of Britain’s favourite branded foods may have risen much more sharply than overall inflation of almost 15%, and that prices of specific products can differ significantly across supermarkets.

Sue Davies, Which? head of food policy, said: “Our research shows the shocking rate of inflation on some of the nation’s favourite branded foods, which is much higher than the national average and highlights why it is so important for retailers to provide people with a choice of product ranges.

“Supermarkets must ensure budget lines for healthy and affordable essential items are widely available across their stores including smaller convenience stores.

“Promotions should be targeted at those most in need and people supported so they can easily compare the price of products to get the best value.”