This depends on the terms of your lease. Normally the landlord will serve a Terminal Schedule of Dilapidations setting out his claim. The maximum amount of your liability is the diminution or reduction in the value of the landlord’s interest in the property and therefore he/she may only claim for his/her actual loss, e.g. the cost of works, if it is lower than the diminution in value. If the landlord intends to demolish or carry out major works when you vacate he/she may not have a claim at all. This is a very specialised area of professional work and you should obtain expert advice as soon as possible.