depends on when leak occurred. If the leak is ongoing over period and would have commenced when previous insurer was on cover, then previous insurer would have to pay a contribution. AFAIK, the current insurer must deal with the claim and chase up the previous guys. If the leak was a sudden one, occurring since you took ou the policy, then current insurer will deal in full. if there is a short perios sonce taking out policy and the notification of claim, curent insurer will want to be sure that (a) you were previously insured and (b) when the leak occurred. They will not pay if you took out the policy after you noticed the leak.