I happen to know that the Call sign for Central Counties Air Operations Unit is "AIR ONE" ( Not difficult to work out why ), while West Midlands Police have "ALPHA OSCAR ONE" - which originally stood for "Air Operations One" ( If they ever buy a second aircraft it would probably have the call sign "ALPHA OSCAR TWO", while at East Midlands Air Support their call sign is a much less obvious "HOTEL X-RAY FIVE FIVE" ( Doesn't exactly trip off the tongue either
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