Only someone with the heart of a concrete robot could fail to feel faintly – just faintly – sorry for the American diplomats whose cables were leaked, what with all that private unguarded chit-chat being made public. If the world had an annual end-of-year office party (which, come to think of it, is a brilliant idea), 2010's would be an awkward affair.

Still, what's most surprising about the mass leak isn't the content – it'd have been more astonishing if they'd said Berlusconi was actually rather charming and North Korea is great in bed – but the fact that this kind of thing isn't happening every day. Because in our terrible modern hell, it's possible for absolutely anyone to leave a comprehensive dossier of ultra- sensitive private information about themselves on the back seat of a bus just by misplacing their phone.

The more these devices are capable of, the greater potential for embarrass-ment. What's on your handset? Intimate texts? Embarrassing photos? Raunchy emails? An eye-opening internet history? I just hope you trust the staff down the Orange store next time you're upgrading your phone.

Actually, if you're anything like me, you don't have anything lurid on your handset at all – partly out of sheer paranoia – but still can't help feeling anxious whenever someone asks to borrow it. It's the same uneasy frisson you feel when a policeman looks you in the eye while stopped at the lights – a vague sense of guilt, like you're hiding something.

And phone-borrowers don't even have to be deliberately nosy to stumble across your personal details. Even if they only want to make a call, simply by accessing the dial option they'll be treated to a list of who rang you last and how long you spoke for. On the phone to the doctor for an hour were you? That's interesting. Here, have it back. Just going to wash my hands.

Another example of inadvertent intrusion: I once used a computer belonging to someone I knew, and logged on to Amazon to look up the release date for a DVD. That's how I roll. I'm crazy. Anyway, the moment I arrived at the home page, it assumed I was her, and presented me with a list of suggested purchases, all of which were self-help books for people trapped in terrible relationships, with titles such as STOP CRYING, START LOVING and WHEN SEX IS HARROWING. It was an uncomfortable and rather sad glimpse into someone else's life, I thought, once I'd stopped pointing and laughing.

Still, at least that was nothing more harmful than someone's innermost thoughts being laid bare. But it's not just our personal information that's increasingly insecure. It's our personal persons.

Not so long ago, a tourist couple stopped me in the street and asked me to take a snap of them grinning in front of something vaguely picturesque (this being London, probably an especially colourful pavement puke-puddle or a tramp with a funny neck tumour). But unfamiliar as I was with the workings of their phone, instead of taking their picture, I inadvertently brought up the gallery of previous photographs, and was treated to a view of one of them in the shower, followed by a series of close-up views of various biological and overwhelmingly intimate occurrences involving the pair of them.

As I fumbled with menus, trying not to betray my embarrassment, I glimpsed at the man and something in his eyes told me that he knew, somehow, what had happened, but couldn't snatch the phone off me for fear of embarrassing his girlfriend, who remained oblivious. Eventually I took the photo. His smile was fixed and unconvincing. I handed the device back. She thanked me. He stared at the ground. We went our separate ways in silence. Somehow, it was as if we'd all taken part in a terrible threesome.

This kind of acute personal embarrassment simply wouldn't have been possible 10 years ago. But with our every folly entered into an electronic ledger somewhere, it's becoming commonplace. Scarcely a week goes by without a leaked nudey phone photo of some hapless celebrity doing the online rounds. Paris, Britney, Rihanna, Miley . . . eventually we'll be treated to raunchy snaps of Mahmoud Ahmadinejad or Vince Cable. Don't pretend you'll turn away. You'll stand and stare like the rest of us.

And those are just the famous people. By the year 2022, there'll be a naked photo of everyone on the planet lurking somewhere in the interverse. You might as well take a really good one this afternoon, while you're young and pliable, and upload it yourself before some future peeping-tom equivalent of WikiLeaks does it for you. Face it: there's a 45% chance that Julian Assange is rooting through an exhaustive collection of photographs of your bum right this very minute. And you know he'll release the least flattering ones first. So you might as well beat him to it.