Insurance woes

Is it possible to insure someone else’s property? Our house insurance doesn’t cover the damage caused by our water pipe to the downstairs flat. They only cover our house. So I rang AXA, our insurer, to look into purchasing a policy for her flat so we’re covered next time should this happen again but they won’t sell it to us. Why not? What do other people do in this situation?

AXA have said our neighbour needs to claim on her own insurance but she has said she doesn’t want to do this since it wasn’t her fault. We’ve only just moved in and since we have to live nearΒ her we’ll just have to pay out of our own pockets. I’ve resigned myself to not getting a new bicycle now. But I don’t want this to ever, ever happen again. How can we purchase insurance for a property we don’t own? Any Brits know how this works? I wish we hadn’t bought a house.