More than three quarters of shoppers who made a special trip to a supermarket to buy an advertised promotion found an empty shelf, according to a survey by the Institute of Promotional Marketing.

Sixty four per cent of shoppers blamed the retailer for out-of-stock promotions, the survey found, while a quarter said they would shop elsewhere. One in seven blamed the manufacturer.

Failing to deliver an ­advertised promotion also made shoppers cynical about future promises from the retailer.

Half said they would be less likely to respond the next time the retailer advertised a promotion. "When retailers decide to advertise a promotion they don't always let everyone in the supply chain know everything that's going to happen and there isn't ­always time to react," said James Murray, director of Fairview Associates.

"The sales volume uplift is so significant in the 24 hours after a promotion is advertised there's no way a store can hold on to that much stock unless it's fully prepared.

"Retailers give suppliers amazing access to store-level demand and availability but not everybody uses the information in the way they could, and not all suppliers have the traction with the retailer."

The results of the IPM survey come as the OFT continues its investigation into misleading pricing ­including 'baiting', where shoppers end up buying a more expensive product because of low availability of the discounted product.

"I am sure that the OFT will be very interested in these results," said Colin Harper, IPM director of insight. "They may want to look at a guideline on how long an advertised offer should be available for. 'When It's Gone It's Gone' seems an inadequate level of shopper protection."

Forecasting needed to be accurate, and preferably based on independently ­accepted methods, added Harper. "It would be much better for the industry to self-regulate than to suffer further external regulation."