Local Government (Miscellaneous Provisions) Act 1976

5 Unauthorised marks on highways

(1) A person who, without either the consent of the highway authority for the highway in question or an authorisation given by or under an enactment or a reasonable excuse, paints or otherwise inscribes or affixes any picture, letter, sign or other mark upon the surface of a highway or upon any tree, structure or works on or in a highway shall be guilty of an offence and liable on summary conviction to a fine not exceeding £100 or, in the case of a second or subsequent conviction under this subsection, not exceeding £200.

(2) The highway authority for a highway may, without prejudice to its powers apart from this subsection and whether or not proceedings in respect of the matter have been taken in pursuance of the preceding subsection, remove any picture, letter, sign or other mark which has, without either the consent of the authority or an authorisation given by or under an enactment, been painted or otherwise inscribed or affixed upon the surface of the highway or upon any tree, structure or works on or in the highway.