Patrick Bousquet-Chavanne, Executive Director, Customer, Marketing & M&S.com, Marks & Spencer, said that online operators' very fast real time response is something legacy retailers need to try and copy. “You have to correlate information, it shouldn't just rest with one team, you need to bring metrics that bring end to end,” he said, explaining that M&S had tried to bring together its diverse insight.

Dr Barbara Kahn, Chaired Professor of Marketing, The Wharton School, University of Pennsylvania, added: “Personalising is not rocket science but actually pretty hard to do, so often retailers get it wrong. Even though the concept of linking makes sense. But big data and aritificial intelligence allows you to be smarter and personalise. To make sense for the consumer.”