Buying a tenanted house in UK (London).?

They have a legal right to stay there until their contract ends. As it usually takes a while for everything to go through and for you to get the keys then this won't be that big a deal for you, you will just have to wait a while to move in, but you will be recieving their rent from them which will cover your mortgage payments for that time. Tenants should have paid a deposit to safeguard against any damage, and if they do anything crazy like totaly trash it then you can take them to court for damages. You could also get the estate agents to manage the property for you, which will cost you a monthly fee but it means that they deal with literally everything for you, including inspecting the property when they move out and dealing with damages and chasing up money. This is good if you have never had any experience with tenants before.