Four out of five UK retailers are failing to respond to the increasing mobile habits of shoppers, according to a study. The study found that only 7% of major retailers have a mobile marketing strategy in place for non-iPhone smartphone users, despite these devices making up over three quarters of UK smartphones. Additionally, only 1% of retailers apparently use wider mobile marketing strategies such as couponing. The director of the company that conducted the study warns retailers to look at opportunities to capture mobile numbers from shoppers in stores, in order to reach them during shopping trips.