Beijing has weaponised an app that gives access to the browsing history of millions of mobile phones and is detaining owners who look at “highly dangerous” foreign financial websites. The National Anti-Fraud App, launched in March by the ministry of public security, has been installed on more than 200 million phones. It is promoted as a safeguard against online fraud but is believed to be used as a surveillance tool. Two people in China told the Financial Times that they were called in by police after looking at foreign financial news services, including Bloomberg, which were labelled “highly dangerous”. Neither…