376.There is no comprehensive statutory legal definition of a highway (but see the limited definition in section 328 of the Highways Act 1980), because the concept of a highway long pre-dates highways legislation. Under common law, a highway may be broadly defined as a way over which all members of the public have the right to pass and repass. The highway authority is the body responsible for maintaining the highway where it is a highway maintainable at public expense.
377.The London Government Act 1963 largely brought the highway law affecting London into line with that applying elsewhere. This is now consolidated in the Highways Act 1980 (the 1980 Act). One difference was that in Greater London there was a 3-tier hierarchy of highway authorities. The Secretary of State was highway authority for trunk roads, the Greater London Council (GLC) for "metropolitan roads" and the London borough councils for all other roads. "Metropolitan roads" were abolished along with the GLC by the Local Government Act 1985, and some of them became trunk roads and the rest borough roads. One purpose of the Act is to reduce the number of roads designated as trunk roads in London and to create a network of key roads for which the GLA will be highway authority.
Commentary on Sections Part Iv: Transport Chapter Xiii: Highways