Tapping a GSM mobile phone conversation is particularly difficult and expensive, according to a special investigator, Mr Liam Brady. The equipment, shipped in from Britain, would cost anything from £40,000, Mr Brady said.
Anyone tapping a GSM phone has to be near the person they have under surveillance, within a two- to 10-mile radius depending on the size of the network cell used. Unlike the analog phone system which can be tapped easily and cheaply, the GSM network carries digitised information which has to be decoded. The surveillance equipment acts as a substitute phone switch so that the calls under surveillance are routed through a PC, rather than a network unit.
In some situations the software alone would cost £43,000, Mr Brady said. "The system is so difficult to tap into, it's just not on."
About a dozen former Defence Forces Ranger soldiers trained in anti-terrorist surveillance are available for hire, Mr Brady said. "They're excellent operators."
However, they would not usually be trained in electronic surveillance. Mr Brady said criminals were reported to be using such equipment last year, but it was not true.
"The last person in the world you want to follow is a journalist," because they tend to be moving around, meeting people in hotel rooms or their own offices. Anyone putting surveillance on a journalist would tap their home phone as a matter of course. "You wouldn't even bother going near their office," Mr Brady said.