MOST of us carry around a pocket computer as a matter of routine. We call them mobile phones - but they do far more than make calls, as last week made clear.

The latest models can take pictures, which created a new, instant form of reportage. Images of the inside of a smoky, wrecked Tube carriage captured by shocked passengers on their mobiles took the world to the heart of the horror.

Meanwhile, many Londoners' first knowledge of the disaster came from a text message: "R U all right?"

Now a terrifically simple idea could give the mobile another role in emergencies: the ICE system.

Just type in ICE, for In Case of Emergency, add the name and number of the person you would like to be contacted in a crisis, and save this into your phone's memory.

If the worst should happen, the ambulance crew will find the number and reach your loved one without delay. The value of this system goes far beyond a terrorist attack: it would work equally well for the victim of a heart attack or road crash.

Ironically, last Thursday's disaster brought down some mobile networks. The value of phone boxes was rediscovered - a cautionary tale for BT, which wanted to close many North Yorkshire kiosks last year.

But as the ICE number can be relayed from the scene of an emergency to the control room, the system will work even if your mobile doesn't.

Updated: 10:22 Friday, July 15, 2005