s 137A Introductory tenancies that are to become flexible tenancies
(1) Where this section applies, a tenancy of a dwelling-house in England that ceases to be an introductory tenancy and becomes a secure tenancy in accordance with this Chapter becomes a flexible tenancy for a term certain. (2) This section applies if, before entering into or adopting the introductory tenancy, the person who became the landlord under the tenancy served a written notice on the person who was or became the tenant under the tenancy— (a) stating that, on ceasing to be an introductory tenancy, the tenancy would become a secure tenancy that would be a flexible tenancy for a term certain of the length specified in the notice, (b) specifying a period of at least two years as the length of the term of the tenancy, and (c) setting out the other express terms of the tenancy. (3) The length of the term of a flexible tenancy that becomes such a tenancy by virtue of this section is that specified in the notice under subsection (2). (4) The other express terms of the flexible tenancy are those set out in the notice, so far as those terms are compatible with the statutory provisions relating to flexible tenancies; and in this subsection “ statutory provision ” means any provision made by or under an Act.