Boundary fence damage due to neighbour's tree

Maintenance

My property backs on to another property who have out of control Ivy growing up and over the boundary fence. I have always trimmed our side of the ivy that grows over. During the recent storm the pressure on the overgrown ivy caused the concrete posts and boundary fence to collapse. I have cleared the storm damaged fence posts and growth on our side (whilst the neighbour looked on without any offer of help). Now this is
cleared I can see the ivy tree and massive roots are now over the boundary line. I cannot physically move these, they are far too heavy. We are unable to put up a new boundary fence without the neighbour getting rid of his tree and roots. He is refusing to do this and says he'll just leave it as it is. It will be a massive job as the ivy spreads for many metres along the boundary line, with very thick visible roots. It is on course to pull other parts of the boundary fence /concrete posts down. Is there any way I can force the neighbour to remove the Ivy tree and roots as it infringes on the boundary and on my land? The weight of this tree is definitely the cause of the damage in the first instance. If he doesn't contribute to the new fence fair enough, but I can't even proceed with any works until the tree is unrooted. Thanks if you can advise.