Residents have a legal right to trim overhanging branches or encroaching roots originating from a neighbour’s tree or hedge. This being that you do not trespass, cause, or facilitate undue damage, that may result in the failure or decline of the relating trees.
You can only trim or prune vegetation back to your property’s boundary line. Unless an agreement has been made, with the relating persons.
This may need to be notified if within a Conservation area or a Tree Preservation Order (TPO) is present.