Residential Tenancies Act 2004
Purpose of Part.
57.—The purpose of this Part is to specify the requirements for a valid termination by the landlord or tenant of a tenancy of a dwelling, whether the dwelling is—
( a) one to which this Act applies but to which Part 4 does not apply (by reason of the operation of section 25 ), or
( b) one to which both this Act and that Part applies (in which case those requirements are in addition to the requirements of that Part with regard to the termination of a Part 4 tenancy or a further Part 4 tenancy).