The Chancellor recognized that the practise would be useful for police and prosecutors fighting crime and called for changes to the law.
Police and prosecutors occasionally deploy telephone surveillance to gather information and evidence about suspected criminals. The information can be gathered when the suspect receives or makes a telephone call.
According to a complaint submitted to the Chancellor police also used telephone signals to track the location of suspects.
Contrary to current telecom surveillance legislation, the Chancellor ruled on Friday. Telephones must be in active use in order for them to be legally tracked.
It is also illegal for telecom operators to release information over the location of suspects. Police and prosecutors are neither permitted to request information from operators nor to receive it, the Chancellor concluded.
The Chancellor recommended a revision of current legislation to allow for the practise as those fighting crime need the additional tools.