You must apply to deregister your motor vehicle if it:
The registering authority will then issue a deregistration certificate. A motor vehicle that has not been licensed for four years will be deregistered automatically.
The application will be processed on the same day.
The service is free but penalties and arrears may be charged if the application is late.
Application for deregistration of vehicle (ADV) form.
Forms are obtainable from the registering authority or you can download them from the eNaTIS website.
Contact your local department of transport