Increasingly our lives revolve around our mobile phones. And we are right to be paranoid.

If we are not already we will soon be using our handsets for everything from banking to browsing the internet, emailing, messaging and listening to music, watching videos, taking photographs and social networking, checking train and plane times, getting directions and finding restaurants, doing office work, keeping our diary, buying stocks and shares, playing games, shopping via m-commerce, and even as a substitute for cash.

Occasionally we might find the time to just dial a number and call another human being.

So were we to mislay our phones we would literally, in certain circumstances, be lost.

But worse, in the wrong hands, our lives would cease to be our own.

Someone else would have all the information they needed to be us.

They would know how to contact our colleagues, our friends, and access our bank account. They could see both where we had been and where we might be planning to go. They could discover what we had been doing, with whom we were communicating, what was sometimes said, as well as what we had been working on.

In all probability, we would have very few secrets left.

Clearly, password protecting our phones makes sense.

As does making a record of our Handset Serial Number and keeping it in a safe place. To get the Number, simply key in *#06# to obtain the 15 digit code. Then, should your phone be lost or stolen, contact your network operator. By providing them with that code they can render your handset inoperable, even were the thief to change the SIM.

However having your Handset Serial Number, although it may save you the cost of a few calls, is not going to protect your personal data. And there is no guarantee that password protection will prove any more successful.

iPhone owners might like to sign up to MobileMe. The service not only enables them to locate their phone via GPS, useful if left in a restaurant, but also to remotely wipe it clean of all data.

Worryingly, even with that facility, you do not have long to beat the race against time. Lose sight of your handset for no more than a few minutes, and its entire contents can be copied.

In that event, the first you would know would be when bad things started to happen.

Law enforcement agencies already have access to a piece of equipment called the Cellebrite Universal Forensic Extraction Device. This portable device, not much larger than a chunky netbook, can allegedly extract data from 95% of all current cellphones.

All the user need do is connect the device to a handset, identify the handset type in the device menu, and hit the start button to begin extracting the phonebook, text messages, call history, audio recordings, video, pictures and images, the phone details and the SIM ID.

Of course, you may not worry about the state being able to access the contents of your phone. What might be more worrying is the possibility Cellebrite technology could fall in to even more malevolent hands.

The reality is, no matter how careful you might be, your handset is insecure, the more so because it is portable and easily mislaid.

The only guaranteed way to keep data safe is to commit it to memory, and not of the magnetic kind. Unfortunately that solution is usually impractical and often ineffectual.

For example, when did you last forget a birthday or where you left your phone?