The Broadmoor Sirens were a series of thirteen warning sirens based in towns and villages surrounding Broadmoor Hospital in Crowthorne, Berkshire, England. They were first installed in 1952 and are based on air raid sirens with the intention of warning residents living near the high-security psychiatric hospital of an escaped patient, with special shutters fitted to allow for a Hi-Lo tone to differentiate them from air-raid sirens.