A s 25 notice can only be given by the ‘landlord’, as defined in s 44(1) of the 1954 Act. Such a landlord is referred to in Sched 6 to the 1954 Act as ‘the competent landlord’ and is not necessarily the immediate landlord. A notice which is served by someone who is not the competent landlord will be invalid, as happened in Yamaha-Kemble Music (UK) Ltd v ARC Properties Ltd, where the assignor of the reversion served a notice following completion of the assignment of the reversion. For the possibility that such a defect could be waived, see A notice may be served by a duly authorised agent of the landlord (Tennant v London County Council; London County Council v Farren [1956] 1 WLR 1297, CA).