More than one in five of the world's 1.9 billion smartphone users are blocking ads when browsing the web on their devices posing a "serious threat" to firms relying on advertising revenues, new research suggests.
At least 419 million people are blocking ads on smartphones, up 90 percent between January 2015 and January 2016, according to report by analytics company Priori Data and Pagefair, a firm that helps publishers battle adblockers.
There are also now twice as many mobile ad-blockers than desktop ad-blockers, as an increasing number of people begin to browse the internet more on their smartphones.
Of the total ad-blocking users, in March, 408 million people used an ad-blocking browser on their smartphones, which block ads by default. Browsers such as Adblock Plus and Brave are an example of this.
Apple's Safari for iOS 9 on the iPhone is compatible with ad-blocking software for example, but it is not the default setting so was not included in Pagefair's calculation.