The Office of Fair Trading (OFT) has sent a stark warning to retailers about misleading price promotion offers.

The OFT said it will take action if it finds that retailers are breaking the law by not making price offers clear.

It highlights promotions such as ‘drip’ pricing, where compulsory costs, such as delivery charges, are added during the buying process.

Other practices it is concerned about include time-limited offers such as ‘offer ends today’, and products with limited stock, such as deals on Champagne.

The OFT said such promotions were not unlawful, but could be against customers’ interests.

John Fingleton, OFT chief executive, said: “It’s an important issue because it affects all of us as consumers, but it’s also important because it affects how markets work across the British economy.

“Today we are urging businesses to review their pricing practices in the light of our report and we will, where necessary, take enforcement action against firms that don’t have their house in order.”

Tom Ironside, British Retail Consortium director of business and regulation, said: “Customers aren’t stupid. They make sophisticated judgements about prices and value within stores, between stores and over time and have all the information they need to do that.

“Discounts and promotions are part of our highly competitive retail market and customers benefit from them,” he said.

The BRC said that there were currently a record number of promotional deals on offer, at a time when household budgets were feeling the squeeze.