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1. old bill
(UK) police
Slasher Smith got turned over by the Old Bill
2. old bill
A word used to describe the Police (UK) or a nob. both inevitably are the same thing.
Kris: what do you think he'd do if i got my old bill out and slapped it down on the table.

Kris: i got fackin chased by the old bill the other day, i only went and charlie sprinted into a police van.