Shoppers are increasingly familiar with the technology behind credit cards that will lead to inquiring calls from card issuers when they feel spending patterns have altered suddenly.

Now, the same applications are being adapted to mobile phones based on the call patterns of owners. The technology developed in Britain uses information on numbers called, length of calls and when they are made to build a user's profile.

By using pattern recognition software, the system can pick up strange usage and send a text message to the mobile phone to confirm the pin number to verify their identify. On a "pay-as-you-go" phone, users will be asked to increase their credit to confirm they are the rightful owners. The phone will be cut off if users do not comply.

Many might find it reassuring to know someone is looking out for them; others will see eerie echoes of big brother.

Dominic Coyle is at dcoyle@irish-times.ie