Any agreement relating to a tenancy is void to the extent that—
it would apart from this section have effect to exclude, modify or otherwise frustrate the operation of any provision of this Act, or
it provides for—
the termination or surrender of the tenancy, or
the imposition on the tenant of any penalty, disability or liability,
in the event of the operation of any provision of this Act, or
it provides for any of the matters referred to in paragraph (b)(i) or (ii) and does so (whether expressly or otherwise) in connection with, or in consequence of, the operation of any provision of this Act.
To the extent that an agreement relating to a tenancy constitutes a covenant (whether absolute or qualified) against the assignment, or parting with the possession, of the premises demised by the tenancy or any part of them—
the agreement is not void by virtue of subsection (1) by reason only of the fact that as such the covenant prohibits or restricts any such assignment or parting with possession; but
paragraph (a) above does not otherwise affect the operation of that subsection in relation to the agreement (and in particular does not preclude its application to the agreement to the extent that it purports to regulate the giving of, or the making of any application for, consent to any such assignment or parting with possession).
In accordance with section 16(1) nothing in this section applies to any agreement to the extent that it is an authorised guarantee agreement; but (without prejudice to the generality of subsection (1) above) an agreement is void to the extent that it is one falling within section 16(4)(a) or (b).
This section applies to an agreement relating to a tenancy whether or not the agreement is—
contained in the instrument creating the tenancy; or
made before the creation of the tenancy.