At common law the tenant has no obligation to keep the premises in a good state of repair but does have an obligation to use the premises in a "tenant like manner":

..In short, he must do the little jobs about the place which a reasonable tenant would do. In addition, he must, of course not damage the house, wilfully or negligently; and he must see that his family and guests do not damage it: and if they do, he must repair it. But apart from such things if the house falls into disrepair through wear and tear or lapse of time, or for any reason not caused by him, then the tenant is not liable to repair it.  Warren v Keen /1954/ 1QB15.