Advertisers are aiming to target where we look when we use the camera on our phone. By Daniel Glaser

Apps that block online adverts have never been so popular - they are the most-downloaded on Apple’s new operating system, iOS 9, which launched last week. But if you already find big banners and self-starting videos annoying, what’s coming next is truly terrifying.

Advertisers are developing ways of tracking our eye movements through the forward-facing camera on our phones. When that happens, there will be nowhere to hide: what you look at gives away what you’re really interested in. It’s even possible to predict the spot the eyes are heading to and plant a nice juicy advert there for when they arrive. This could make for a very uncomfortable browsing environment.