Handset theft: BT and Vodafone finally make their move

Vodafone and BT Cellnet have performed a u-turn today by unveiling the details of new security measures that will enable them to disable stolen mobile handsets.

The move to implement the new technology - which was first revealed yesterday on silicon.com - will bring both organisations into line with the rest of the UK's mobile operators, which are already utilising software that disables phones once they've been reported stolen.

Their system is based on the international mobile equipment identity (IMEI) number assigned to each handset. In theory, every phone sold has its own IMEI number and if a user reports the details to their operator after it's stolen, the operator should be able to stop the handset being used on any network thereafter.

BT Cellnet and Vodafone originally refused to get involved in a scheme based on IMEI numbers as they believe it's ineffective, simply because it is possible for more than one handset to have the same IMEI number.

A phone that sports a shared IMEI number cannot be barred from the network without all the phones with the same number also being blocked.

A Vodafone spokeswoman said she was not at liberty to divulge the number of multiple IMEI numbers in use on the Vodafone network, but said: "You could have an infinite number of IMEIs the same."

However, Vodafone has confirmed its software will enable it to trace shared IMEI numbers so the stolen phone's SIM card can be remotely disabled instead.

But, the Vodafone spokeswoman admitted thieves could simply change the SIM card in the phone and continue using the handset.

"IMEI barring is not a perfect system. There are a lot of people that will work very hard at defrauding the system no matter what we do."

A spokesman for BT Cellnet said the company had not yet decided on precisely what technology to use on its own network, but that it will have the same functions as Vodafone's system.

"We are also upgrading our system so after we have traced the phone using its IMEI, we can let a couple of calls through for the police to listen to, in case the thief is talking to Mr Big or something.

"Multiple numbers are the reason why these systems alone won't be complete. We and the other operators are pressing the Home Office for legislation to outlaw changing the numbers."

Both companies will share all their information gathered on stolen phones in a shared database that will also be accessible to other operators and the police.