A new mobile phone technology increasingly being used by businesses could present a security threat as it provides better anonymity for cyber criminals, warn experts.
Femtocells are short-range base stations typically used to boost coverage in buildings or to combine fixed and mobile networks.
The boosters are being widely introduced as landlines are dropped and improved mobile coverage is needed.
But the devices represent a challenge for tracing criminals, according to Lord Toby Harris of the House of Lords science and technology committee.
"The challenge these signal boosters will pose in terms of policing is going to be enormous," he said.
Femtocells allow the authorities to trace internet criminals’ IP address as far as the base station. But finding the phone that connected to the device is much more difficult.
The same problems apply to all types of mobile internet access, said Richard Clayton IT security expert at Cambridge University
"This is a generic issue with accessing the internet via mobile phones – peer to peer mobile phone contact has also provoked serious concerns," he said.
Last year, some mobile phone companies trialled technology that allowed free communication between mobiles without the need for a base station.