bit late on this post but I don't see why this has only just surfaced, the police already have the ability to monitor mobile phones
and anyone with a receiver with the correct frequency can tune in, I can remember back in '81 radio shack used to do a unit that you could tune into almost anything that was being transmitted , it was of course not very legal and was soon withdrawn,
on the other hand if you've been nicked they will take your phone and go through it with a fine tooth combe and you won't get it back until your either released from bail or your properly nicked, the one thing to do if this does happen to you is get ride of your phone and change your number, me, paranoid ? never.
or have I got the wrong end of the stick as usual
IGMC