Roots.
If the roots of a neighbour's tree
spread into a property, they can be removed
using the least damaging method available,
(see Tree preservation orders). If a
neighbour has to enter the tree owner's
property to do this, s/he must give
reasonable notice.
The neighbour may also wish to consult
her/his insurers, if there is a possibility
that her/his property may be damaged by the
roots. If the roots have already caused
damage, the tree owner is liable to pay
compensation but it must be shown that the
tree owner knew, or ought to have known, of
the danger.