Supermarkets have been slammed for continuing to offer “dodgy” special offers and discounts, despite the introduction of government rules designed to stamp out such deals.

Consumer group Which? found a host of “dubious” deals were still being offered by some of the UK’s biggest grocery retailers.

The offers included multi-buys that cost more and special offers where products were sold at the special price for most of the year rather than a limited time.

Which? analysed the prices of 459 products between May 2018 and June 2019 across seven different grocery retailers: Tesco, Sainsbury’s, Asda, Morrisons, Waitrose, Iceland and Ocado.

The group highlighted a number of “dodgy” offers, such as an Iceland multi-buy, where customers were offered two packets of Kellogg’s Crunchy Nut for £4. But Which? found that the price of one box of the cereal was just £1.49 a week earlier – 51p less per item than the special offer.

Asda was found to be selling Wall’s Carte D’Or strawberry ice cream under shelf labelling that read “was £3.50 now £2”. Which? said the product retailed at £2 for around eight months of the year, but the special offer only lasted for around a third of that time.

The latest findings from Which? came four years on from a previous investigation into misleading supermarket pricing. The probe prompted the government to roll out new guidance to ensure that retailers’ pricing practices complied with consumer law.

Rules now state that retailers have to present fair information to customers and do no waste shoppers’ time by presenting confusing offers that cause annoyance, disappointment or regret.

Offers also should not cause customers to overspend or buy a product that is inappropriate for them.

Which? head of home products and services Natalie Hitchins urged the Competition and Markets Authority (CMA) to step in to stamp out the misleading offers. She said: “Many of the big supermarkets are clearly still in the wrong, with numerous examples of dodgy discounts and never-ending offers.

“These retailers must stop tricking shoppers with deceptive deals… if not, the CMA must intervene to ensure that pricing guidelines are followed.”

An Iceland spokeswoman said: “We update our promotions throughout the year to offer the best possible value to our customers, and review our approach to pricing structures to ensure savings to the customer are as transparent as possible. We have incorporated the findings shared by Which? into this process and will continue to review and improve our promotional calendar.”

A BRC spokesman said: “Supermarkets seek to provide the best value for consumers on the hundreds of thousands of product lines they sell.

“This is often through promotions and discounts, which can change week to week, even on the same product lines, as retailers seek to cut the cost for shoppers.”