The UK’s competition watchdog is challenging Apple and Google’s “effective duopoly” over mobile platforms by allowing developers to steer users away from their app stores to make purchases.The Competition and Markets Authority argues that consumers and app owners are being let down by Apple and Google restrictions on spending money outside their app stores.The regulator has described both tech companies as operating an “effective duopoly” with at least 90% of UK mobile devices running on their platforms.The ...