Telecoms giant BT is to use a new technology system to tackle cable thieves in a move police believe will act as a "major deterrent" to criminals.
The Rapid Assessment BT Incident Tracker - or Rabit - constantly monitors the BT network and detects when a disconnection has taken place.
A trial has already forced thieves to flee empty-handed when they tried to steal some cable in Essex.
Luke Beeson, general manager of BT Security, said: "BT's new burglar alarm on the network will make thieves think again.
"We are now able to inform the police of the exact location of malicious network attacks and, if trials are anything to go by, it won't be long before they start catching the thieves in the act."
Paul Crowther, deputy chief constable of the British Transport Police, said: "In my view, this technology will significantly improve police response times to cable theft incidents and will act as a major deterrent to criminals engaged in this activity.
"More importantly, communities and businesses should see a sharp reduction in the disruption caused by this type of theft."
BT has recovered 240 tonnes of stolen metal in the past 11 months, while the number of arrests has risen to 480.