The Upper Tribunal case of Westmark (Lettings) Ltd v Peddle has provided some welcome guidance on when service charge costs are "incurred" by a landlord for the purpose of complying with section 20B of the Landlord and Tenant Act 1985 ("the Act").  Section 20B of the Act provides that a claim for costs incurred must be made against relevant leaseholders within 18 months of such cost being incurred.  Where there is a chain of landlords it is now clear that the costs are not incurred by each individual landlord until that particular landlord becomes liable to pay them.