Supermarkets deliberately manipulate and mislead consumers through "misleading" discounting promotions, a UK consumer group claimed today (20 November).

According to a study conducted by campaign group Which?, UK retailers regularly break government guidelines for discounting.

The Consumer Protection from Unfair Trading Regulations Act, introduced in May, states that before an item goes on offer, it should be at the advertised higher price for 28 days in that store. However, the consumer watchdog found that the UK's major retailers fail to follow these rules.

Which? found Marks & Spencer sold "half price'' cherries for GBP2.49, when they had actually only cost GBP2.99 before being put on offer. Waitrose blueberries were advertised as being half price when they had only ever been at the higher price for two weeks.

Meanwhile, Tesco strawberries and Marks & Spencer bacon were 'on offer' for the whole three-month investigation.

"These offers don't actually break the guidelines, but can hardly be described as 'special'," Which? said.

Nevertheless, a spokesperson for Which? told just-food that these findings do not necessarily mean retailer promotions are bad value.

"They can offer genuine value for consumers, but shoppers do need to be a bit canny about what they buy. Just because something is marked up as having 70% off doesn't mean it is cheap," the spokesperson commented.

Responding to the Which? study, a spokesperson for M&S told just-food: "We always aim to offer our customers excellent value and follow trading standards guidelines on promotions wherever possible."