The use of ‘vanity sizing’, when clothes are labelled with sizes smaller than the actual cut, is also underlining a lack of consistency when it comes to sizing, leaving shoppers feeling confused and frustrated.Research published by The Times found that some size 10 skirts and dresses from high street retailers have a waistline of 32 inches – which is considered a size 16.

The issue could be making shoppers underestimate their own size and the importance of staying active, Tam Fry, chairman of the National Obesity Forum said.“Regrettably vanity sizing has been in vogue for some time as manufacturers and retailers fight to keep their customers happy. The tragedy is that it works, with millions of women still fooled into believing they are keeping their shape when they are not,” he explained.“Statistics show that some 60 per cent are no longer a healthy weight and though the sizing ploy may help their self-esteem in the shop, it does nothing to help their long-term health.”Eight fashion brands including Zara, H&M, Topshop, Marks & Spencer, Whistles and Miss Selfridge were included in the study.Whilst the British Standards Institution has provided guides to standardise sizing, brands are under no legal requirement to comply.A spokeswoman for the BSI said: “Many retailers size their clothes according to their customer base. People prefer to fit into a 12 than a 14 so retailers like to please. As body sizes have got bigger so have dress sizes.”