Who is responsible for maintaining a fence that divides two properties?
The owner of the fence! It sounds simple enough, but as you’re probably aware things can get complicated if you don’t know who the owner is. This can sometimes be established by looking at your title deeds, but if they aren’t helpful it’s likely to be a shared fence, in which case it should be jointly maintained. But having said all that, people are not generally speaking required by law to look after their boundary walls and fences. So if your neighbour has allowed his fence to fall down, or refuses to share the maintenance of a jointly-owned fence, in the absence of a specific obligation in the deeds there may be nothing for it but to build your own on your side of the boundary.