In fact, I am photographing them, taking video clips and wiring them back to the office. I make a call without lifting a finger. I send a discreet email. But I attract no attention because the camera, the screen and the phone are virtually invisible. They are just a tiny component of my high-tech glasses.

I am looking at the future and the people around me are oblivious. The long-awaited but controversial Google Glass has arrived in Britain, and I am testing what it can do – and not just in terms of making calls or capturing high-quality snaps to show my friends. I am also seeing how it stretches long-cherished ideas of privacy to breaking point. And beyond.