Major UK supermarkets including Aldi, Tesco, Asda, Morrisons and Sainsbury's are now legally required to follow updated rules on how prices are displayed on shelves, following reforms to the Price Marking Order that came into force in April 2026.
What the new rules require
The changes standardise unit rates, outlawing the practice of mixing two different measurements on the same shelf. For example, some retailers previously priced one product in kilograms and another in grams, making comparisons more difficult. From now, all price labels must use kilograms, litres, metres, square metres or cubic metres.
The rules also govern loyalty schemes such as the Tesco Clubcard and Sainsbury's Nectar Card, making it illegal to give 'undue prominence' to loyalty prices on shelf labels.
Loyalty pricing and product scope
Solicitors Herrington Carmichael explain: “Where a product is offered at more than one price for example, a standard price and a loyalty price, traders must display both selling prices together and, where unit pricing applies, show the corresponding unit price for each. Traders should state the eligibility conditions clearly and next to the prices, for example, that the loyalty price is available with a valid loyalty card, and ensure neither price is given undue prominence.”
The law has also been extended to cover more products. The firm adds: “Obligations extend to more packaged goods including cereals, pasta, dried fruits, detergents, cleaning products and cosmetics. This is intended to support like for like comparisons on a wider range of everyday items.”
Exemptions and other changes
The rules do not apply to smaller shops with a floor space of less than 280 square metres, so they do not affect corner shops and convenience stores. The law also allows for blanket reductions, such as “20% off all paint”, without forcing retailers to change every label.
Last year, the Express reported how Asda was selling items in contravention of the legislation for several weeks, until it updated its labels on shelves and issued an apology following the reporting. The reforms are designed to ensure consumers can make informed purchasing decisions by requiring clear and transparent price information, particularly where products are sold in different sizes or where promotions, discounts and loyalty pricing apply. The changes expand the scope of unit pricing to more product categories, clarify how selling and unit prices should be displayed where multiple prices apply, and introduce updated definitions, including a new requirement to display deposits separately.
