cracks in my wall due to neighbour's building work

[Guest]

Two weeks ago, my next door neighbour was having some building work done which involved removing a ceiling in the room adjoining one of my bedrooms. On the first day, after a lot of bashing and drilling on the other side, I noticed cracks had appeared in my wall. They and their builders are refusing to discuss the matter. I have written to them and they ignored the letter. I have - by a stroke of luck - evidence that the cracks weren't there before. Who do I take to court - the builder or the neighbour?

[ostell]

The neighbour, who then claims from the builder