The group's analysis of more than 21,000 products at Tesco, Sainsbury's, Asda, Morrisons, Aldi, Lidl, Waitrose, and Ocado found that some prices have increased by as much as 175%.
The Competition and Markets Authority (CMA) is due to release a report on competition and pricing in the grocery sector this month.
The price increases have been driven by increased costs for animal feed, fertilizer, fuel, energy, and labor, as well as poor harvests, bird flu, and a weaker pound.
Supermarkets have absorbed some of these cost increases, but others have been passed on to consumers.
The British Retail Consortium, which represents major supermarkets, says that retailers have not passed on all of the cost pressures to consumers.
However, Which?
argues that the findings show some supermarket products have been hit with disproportionately high inflation.
The group has called on the government to take action when the CMA publishes its report, and has also urged finance minister Jeremy Hunt to provide an update on his progress on agreeing measures with industry to ease the pressure on consumers.
The supermarkets have rejected allegations that they have profiteered during the cost of living crisis.
They argue that they have worked hard to absorb cost increases, which means that the UK offers some of the cheapest grocery prices in Europe.
However, the prices of some key staples, such as butter and bread, have begun to fall in recent weeks.
While the UK government has raised concerns about soaring food prices, it has said it is not considering imposing price caps.
Governments across Europe have been struggling with high inflation, and some, such as France, have secured pledges from food companies to cut prices on hundreds of products.
Hungary has imposed mandatory price cuts.
LONDON DAILY ARCHIVE
UK Supermarket Food Prices Rise by 25.8% in Two Years, Says Consumer Group Which?
A British consumer group, Which?, has called on the government to take action to support households after finding that food prices at major supermarkets have risen by 25.8% in the past two years.
17 July 2023 · 10:24 UTC
