(1)A fundamental term of a secure 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 103(1)(b) and (2) and this section,
(b)section 45 (requirement to use deposit scheme),
(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), and
(h)section 158 (securing contract by use of false statement).
(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 secure contract is of no effect if it would render any 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 secure contracts; section 20 provides that this section—
(a)must be incorporated, and
(b)must not be incorporated with modifications.