After a decade wearing a punishing combination of high heels and heavy bags, fashionable women have apparently had enough. They may not be reaching for orthopaedic shoes just yet, but back-friendly rucksacks are in vogue.

Never mind its associations with maths students and Silicon Valley geeks, it’s a hot fashion item. Sales are up by 30 per cent at Harvey Nichols and Selfridges, and 40 per cent at Topshop. Dull black canvas is out, exotic skins, perforated leather and bold graphic patterns are in.

Among those spotted wearing rucksacks are such style leaders as Rihanna, Kristen Stewart, Kate Bosworth and Alexa Chung. Charlotte Casiraghi included a backpack in her equestrian collaboration with Gucci last season, while the designers Alexander Wang and Pierre Hardy have also