A quarter of shoppers didn't buy everything they wanted during their big Christmas shop because of poor availability, new research has revealed.

The survey of 1,000 consumers revealed 18.4% of those who found a product unavailable purchased a substitute item. The remaining 81.2% bought the product from a different store or didn't buy it at all.

"I'm sure the snow was a factor but it's also a convenient excuse," said Mark Croxton, MD of Aldata, which commissioned the poll. "I find it quite disappointing that a quarter of customers are missing out on something they went in for. It should be a little red flag for the grocery retailers at Christmas time.

"I think some retailers will be surprised," he added. "They're confident they can get over inventory problems by selling a substitute product, but these are lost sales."