Local authorities’ duties in respect of abandoned vehicles stem from the Refuse Disposal (Amenity) Act 1978, as amended by the Clean Neighbourhoods & Environment Act 2005.
The Government’s guidance on abandoned vehicles is published here: https://www.gov.uk/guidance/abandoned-vehicles-council-responsibilities
Where it appears to a local authority that a vehicle in its area is abandoned, it will be its duty to remove the vehicle. This duty applies to all land in the open air or any land forming part of a highway. However, in respect of such vehicles that are not on the carriageway, this duty does not apply where the costs of removing them to the nearest convenient carriageway is unreasonably high.
It is up to councils to decide how best to meet their statutory duties in respect of abandoned vehicles, and how to prioritise this against other local services.