I read someone a while ago complaining that if they handed their phone to a friend to show them a photo, it would be a matter of seconds before said friend was scrolling through all of their photos and seeing stuff they’d rather they didn’t. (There is a temptation here to think that I’m referring to saucy pictures of our protagonist and his or her funtimes sex friend, but it could as easily be snaps of a damp patch our hero has documented in order to bring to the attention of the landlord, and which he or she doesn’t especially want friends asking about.)

Happily, iOS 6 or later has a feature that can help: Guided Access. All you have to do, once you’ve configured it, is to triple-click the Home button as you pass your iPhone to your friend – an action so subtle that they might not even realise you’re doing it (until they try and fail to swipe and find photos of your damp patches, as it were). If you don’t know how to enable it, here’s a quick-and-dirty (though not that kind of dirty) guide with appalling audio and diction: