A new research report says the fees Apple and Google charge on digital purchases made inside apps could cost users in the UK more than £4 billion over the next five years. The study focuses on smartphone and tablet users who subscribe to digital services through mobile applications, arguing that a “stealth” levy embedded in app store transactions can raise the effective price of in-app purchases. According to the report, the additional charge can be up to around 30% and is applied to transactions routed through Apple’s App Store and Google’s Play Store. The research also notes growing public and policy calls for greater scrutiny of these practices, including calls for the UK competition regulator to consider whether the current arrangements reduce competition or create unfair cost burdens for consumers. The findings are presented as estimates of consumer impact over a multi-year period, based on the share of mobile subscriptions and the level of the app store commission cited by the study. The report does not claim changes have already been made, but frames the issue as a cost pressure on UK users if fee structures remain in place.