Highway boundaries
Public highway rights on private land
Whilst public highway rights can exist on land owned by the highway authority, most public highway in England exists on land which is owned by a private individual or company.
The surface of the land on which highway rights exist is the responsibility of the highway authority. This is regardless of whether the land is owned by the highway authority or owned privately.
If the highway is not owned by the highway authority, the adjacent landowner retains ownership of the subsoil beneath the highway as per the 'ad medium filum' presumption.