Supermarkets could soon be required to inform customers when they are effectively being asked to “pay more for less”, under new proposals aimed at tackling “shrinkflation”.
The Liberal Democrats are pushing for an amendment to government legislation that would legally oblige large supermarkets to notify shoppers when the quantity of goods in a pre-packaged product has been reduced, leading to an increase in the price per unit.
Under the proposed amendment to the Product Regulation and Metrology Bill, details of these changes would need to be displayed on or next to the product for a 60-day period.
Research conducted by Compare the Market in 2024 revealed that items such as digestive biscuits, butter, crisps, and chocolate bars have seen a decrease in size while their unit cost has increased.
MPs may vote on the Lib Dem proposal on Wednesday, when the Bill is scheduled to return to the Commons for its report stage.
Lib Dem trade spokesman Clive Jones said: “The scourge of shrinkflation needs to be exposed.
“Shoppers have been hammered during a cost-of-living crisis all while massive companies and big supermarket chains are forcing them to pay more for less to protect their bottom lines.
“They need to be called out on it and for shoppers to know when they are at risk of being ripped off.
“The Government should accept this Liberal Democrat amendment so that we can help protect shoppers and their already stretched household budgets from another round of shrinkflation.”

The Bill as a whole gives powers to ministers to regulate the marketing and use of goods in the UK after Brexit.
It was previously amended in the House of Lords to provide protections to the imperial pint measure to ease fears over its future.
The changes accepted by the Government would bar ministers from preventing or restricting the use of the pint in relation to draught beer, cider or milk in returnable containers.
It also provides a definition of a pint as 0.56826125 cubic decimetres.
A Department for Business and Trade spokesman said: “We’re committed to protecting consumers from unfair commercial practices and making sure they have all the information they need to make informed decisions on purchases.
“That’s why we’re bringing in strict new laws next year to make sure businesses use clearer labelling for prices on supermarket shelves, and retailers show all unit prices in either kilograms or litres to improve clarity for shoppers.”