In 1883 the Home Secretary invited competition from companies to replace the hand rattle that the London Metropolitan Police of the time relied on. Joseph Hudson, basing a new whistle on the sound he had heard when a violin broke from a fall, was awarded the contract for over 7,000 whistles. During testing on Clapham Common, the sound of the whistle was heard over a mile away.
In 1884, the company continued their whistle revolution, inventing the first reliable pea-whistle, the Acme Thunderer, which is still the most popular whistle today and has sold in the hundreds of millions.
Police Whistle photograph by Leo Reynolds