Shrubs and trees etc overhanging
the Public Highway
The owner or occupier of a property has a legal responsibility (Highway Act 1980 s154) to ensure that the 'public highway' adjacent to a property is not obstructed by vegetation from their property.
Local Authorities also have a legal duty to ensure that public highways and street lights are unobstructed, so usually inspect roads regularly and often receive complaints from members of the general public.
The public highway, is defined by law as consisting of any verge, footway, carriageway, bridleway or footpath that is maintained at public expense and over which the public has a right of way.
When Local Authorities become aware of such obstructions, they will usually advise the property owner or occupier of the problem. They may sometimes raise the issue with an owner/occupier even if the vegetation only overhang the pavement/roadway by a small amount - this may seem 'small minded' but where should they draw the line? It is easier for all concerned to use the specified rules.
If the owner/occupier does not take corrective action within a reasonable time (the Local Authority will normally specific a time limit for the work to be completed), the Local Authority can issue a formal notice for the work to be undertaken, and if that is ignored, they can do the work and charge the owner/occupier.
It should be remembered that it is illegal under the Wildlife and Countyside Act 1981 to disturb nesting birds; so carefully check before cutting back or, if in doubt, wait until the Autumn.
The requirements
Although the Highways Act 1980 doesn't specify any actual measurements for overhanging vegetation, the requirement should be met by:
- For pedestrian areas, minimum headroom of 2.3m (7ft 6 inches).
- For carriageway and an area immediately adjacent to it (for a distance of 0.45m (1ft 6 inches)) minimum headroom of 5.2m (17ft).
In both cases, all the vegetation should be cut back vertically. See the diagrams below. 
Trimming over footpath
Trimming over footpath
and roadway