>As it happens, the title of a policeman in UK is PC (Police Constable) except in certain forces where they are just called "constable". So you can have a PC being PC on his PC <s>

Assuming that anything finishing with -able is coming from a verb and forming an adjective meaning "can be ~ed", as in read-readable, pay-payable... then these must be the guys that the police can const all it likes, just like the vegetarians can veget their food.