The Aviation Security Operational Command Unit (SO18), after April 2015 known as Aviation Policing Command (APC) or Specialist Operations – Aviation Policing (SOAP), is a Specialist Operations unit of London's Metropolitan Police Service. The unit is responsible for providing policing and security for both Heathrow and London City airports. London's other airports – Gatwick, Stansted and Luton – are policed by Sussex, Essex and Bedfordshire Police respectively, as they are not located in the Metropolitan Police District.