CA 20 February 2002. The appellant landlord (A) owned a building and let the top floor as four flats to the respondent tenants (B) between 1991 and 1994. Under the tenancy agreements, A agreed to 'keep in repair and working order any installations..', and prior to granting the tenancies A had replaced the pipework with smaller bore pipes. Between 1992 and 1998 the new pipes did not have enough water pressure to carry water to the top floor, but did so after 1998 when the water company built a new pumping station to address the drop in water pressure. It was held by the county court judge that A had not breached his obligation under the Landlord and Tenant Act s11(1)(b) to keep the pipes in working order. B's appeal to the High Court was allowed on the grounds that A's obligation was 'to ensure that the pipes were physically or mechanically capable of supplying water to the flats'. A appealed. "Held": appeal allowed on the grounds that s11(1)(b) required A to ensure that the installation for the supply of water etc. was designed and constructed to perform its function at the commencement of the tenancy, and that the variation in water pressure could not reasonably have been anticipated.