Incoming!

The shopkeeper who sounds a WWII air-raid siren when a traffic warden is spotted
When traffic wardens started to blitz a quiet corner of suburban London, one shopkeeper decided it was his duty to fight back. Martin Herdman put up a 1,000-watt public address system outside his shop near Twickenham and recruited a network of "spies" to alert him the instant they spotted a parking attendant in the area.

Ha, ha. That's the way to do it!