Police in Tenby are warning all mobile phone users to be on their guard after a spate of thefts.
In the last couple of months, police officers in the town have received reports of at least 15 thefts of mobile telephones.
In addition, 32 members of the public have reported mobile phones as lost property.
It has been the case up until recently that when a mobile phone was stolen, all the thief had to do was replace the sim card and they could then use the stolen phone as their own.
It is now possible for the actual mobile telephone to be disabled simply by informing the network operator of its serial number.
To obtain the serial number of your mobile phone simply press *#06#
Record the serial numbers displayed and keep in a safe place.
Should your mobile phone become lost or stolen, inform the network operator who will disable the actual handset.
Inspector Les Clark at Tenby police station said: "Most teenagers these days have mobile telephones and it is often this age group who are victims to theft.
"Make sure you record the serial number of all mobile phones in your family. By recording this information and informing the operator when stolen, you can at least have the satisfaction of knowing that the phone is useless to the thief who stole it in the first place."