The roots of a tree on council land at the side of my bungalow are lifting the tarmac on my drive and could be damaging the drains below. 18 months ago the council agreed the tree should come down, but nothing’s been done despite numerous letters and phone calls from me.
Your buildings insurance may cover damage to drains, in which case your best course will be to make a claim. Your insurers can then pursue a claim against the council. The council will almost certainly be responsible for any damage in the period since you notified it of the problem. Otherwise ask a solicitor to write to the council pointing out that delay could be increasing its repair bill. As long as the tree is not the subject of a preservation order you are entitled to cut the roots at your boundary.