127Limitation on variation
(1)A fundamental term of a periodic standard contract incorporating any of the fundamental provisions to which subsection (2) applies may not be varied (except by or as a result of an enactment).
(2)This subsection applies to the following fundamental provisions—
(a)section 122(1)(b) and (2) and this section,
(b)section 45 (requirement to use deposit scheme) and section 177 (breach of deposit requirements),
(c)section 52 (joint contract-holder ceasing to be a party to the occupation contract),
(d)section 55 (anti-social behaviour and other prohibited conduct),
(e)section 148 (permissible termination),
(f)section 149 (possession claims),
(g)section 155 (death of sole contract-holder),
(h)section 158 (securing contract by use of false statement),
(i)section 175 (restriction on giving landlord’s notice under a periodic standard contract during first four months of occupation), and
(j)paragraph 7 of Schedule 4 (variation of secure contract addressed in written statement of introductory standard contract).
(3)A variation of any other fundamental term (other than by or as a result of an enactment) is of no effect—
(a)unless as a result of the variation—
(i)the fundamental provision which the term incorporates would be incorporated without modification, or
(ii)the fundamental provision which the term incorporates would not be incorporated or would be incorporated with modification, but in the contract-holder’s opinion the effect of this would be that the position of the contract-holder is improved;
(b)if the variation (regardless of whether it is within paragraph (a)) would render the fundamental term incompatible with a fundamental term which incorporates a fundamental provision to which subsection (2) applies.
(4)A variation of a term of a periodic standard contract is of no effect if it would render a term of the contract incompatible with a fundamental term (unless that fundamental term is also varied in accordance with this section in a way that would avoid the incompatibility).
(5)Subsection (4) does not apply to a variation made by or as a result of an enactment.
(6)This section is a fundamental provision which is incorporated as a term of all periodic standard contracts; section 20 provides that this section—
(a)must be incorporated, and
(b)must not be incorporated with modifications.