On Sun, 25 Dec 2016 02:15:10 +0000, James Wilkinson Sword wrote:

What law am I breaking by listening to something that has been broadcast
into MY property?

The key point is that police comms do not fall within the legal
definition of "broadcast" which is a signal intended for general
reception. None of the signals originated between agencies of the
emergency services (fire, police, ambulance, coastguard etc.) are
intended for general reception.