The Western Counties Air Operations Unit was a joint consortium established to provide police aviation for Avon and Somerset Constabulary and Gloucestershire Constabulary. It was formed in August 1995, and operated a Eurocopter EC135 from Bristol Filton Airport. In July 2013 the unit was subsumed into the National Police Air Service, becoming NPAS Filton, though continued to operate from Filton.
References
Western Counties Air Operations Unit Wikipedia(Text) CC BY-SA