Whilst your neighbour is legally allowed to remove both branches and roots
that invade/overhang his land
HE IS NOT entitled to cause damage to the tree
and actually should have first asked you to remove the trespass before he
did anything himself

In reality its time everyone remembered that its realy their resposibility
to retain all plant growth of whatever kind within their own boundaries
.........sadly this is something which has been forgotten and of course when
it comes to Leylandi has caused real Neighbour Hell
"bigjon" wrote in message
...
Our rear garden backs onto the one opposite. We had a lovely young (
12ft )
Snake Bark Maple in the centre of the back border. Our wonderful neighbour
took it upon himself to trim all the growth over all his fences, including
the leading shoot of our tree, which was slightly leaning over his fence (
about 10 degrees, and not casting any shadow, over his 12 x 6 shed roof ).
This has reduced the tree to an upright trunk of about 6 feet and a top
branch of about 6 ft that leans dramatically back into our garden at about
45 degrees. My questions - was he legally allowed to basically destroy a
healthy tree in this way, as it did not cause any real problem to him, and
should I remove the top branch to allow another to become the lead ?