Report a derelict or abandoned building - www.gov.uk webpage
September 10, 2014
In principle, you enter a post code and are then linked to the Building Control section of your local authority's website (in England and Wales). The web-page says:
You can report a derelict or abandoned building to the building control section of the local council.
In practice the process may take you to local authority web-pages that aren't Building Control and don't necessarily give you obvious options to report an abandoned or derelict building (try it in your own area and see where you get).