The competition regulator has given the final clearance for BT’s contentious £12.5bn takeover of EE, Britain’s largest mobile phone network. The Competition and Markets Authority said it did not expect the takeover to lead to a substantial reduction in competition or detriment to consumers in any market in the UK, including mobile and broadband services. It said there was little overlap between BT’s mainly fixed phone, broadband and pay-TV business and EE’s mobile phone operation.