The cost of food is one of the top worries for consumers, alongside energy and fuel. With household finances squeezed, shoppers are searching for bargains. But in many supermarkets, people are being let down by the quality of labelling. And bamboozling pricing displays mean it’s harder to spot a good deal.

Working out the best value between three loose onions at 16p each or a pack of three onions at 87p per kg would involve shoppers having to weigh the onions and do some maths. We don’t think consumers should have to do that.

Unit pricing is a brilliant tool to help people get value for money. It sets out what the price is per 100g, kg or litre, so easy comparisons can be done between different brands and product sizes. Unfortunately, the complexity of the units set out in current legislation, and the inconsistent application in some stores, mean it’s far more confusing than it needs to be. Even for those that do have time to work out the maths, comparisons are sometimes impossible.

“Consumers are struggling to work out how to get the best value”

Which? is campaigning for the law to change to ensure supermarkets ‘Price It Right’ so clear, consistent food unit pricing has to be displayed, even on special offers. Special offers are a particular issue: current guidance lets them off the hook. But as these are now so prominent in supermarkets, it is essential that a price is provided for products bought as part of an offer.

We have received numerous comments from consumers who are struggling to work out how to get the best value for money on their regular supermarket shop. Typical comments include people being fed up with trying to compare prices with varying units. One consumer even said that: “When shopping in supermarkets I always take a calculator to help work out what bargains are good value”.

Which? is calling on the government to simplify current unit pricing legislation to make it easier for retailers and enforcers to ensure unit pricing is clear and consistent. We’ve already had more than 7,000 people support our call.

We’re taking our campaign to Westminster, too. MP Jo Swinson is championing a Private Members Bill - the Price Marking Consumer Information Bill, due to be heard in November - to bring about this change in the law, which is already receiving cross-party support.

Tidying up unit pricing law is a small step for the government to take to help shoppers make the most of their budget at a time when household finances are more stretched than ever before. To pledge your support visit www.which.co.uk/unitpricing.