Just to join in for fun, looking at the law book (I've just done the PPL exam) it states:
"Note that a pilot intending to make a flight must in any case contact ATC (or other authority where there is no ATC) at the aerodrome of departure. This is known as Booking Out and is a separate and additional requirement to that of filing a flight plan"
The only time you have to contact the Police is when arriving to or departing from the UK at a non-designated airfield. In this case 12 hours (Or Even 24 in some regions) must be given to the relevant police department (A fax usually suffices).
Pages 95 and 100 of the Aviation Law and Meteorology book - Air Pilot Publishing - 2006.
So, on an internal flight as long as you Book Out of the airfield, and also get clearance to land where there is an authority in control you are covered.