Antique Metropolitan Police issue whistle. Rare to find stamped with the owners' police issue number (20046), and it works.....and is VERY loud. Identified as an MP-9 model, this was manufactured by J. Hudson of Birmingham. The Metropolitan whistle was first patented in 1884 when J. Hudson secured the first contract to supply various police forces of the UK. The whistle is stamped with the address of 13 Barr Street, Birmingham, which combined with the model number (MP-9) dates this whistle to circa 1900. In excellent original, working condition.