53(1)
A protected shorthold tenancy may be brought to an end (by virtue of this section and notwithstanding anything in the terms of the tenancy) before the expiry of the term certain by notice in writing of the appropriate length given by the tenant to the landlord; and the appropriate length of the notice is—
(a) one month if the term certain is two years or less; and
(b) three months if it is more than two years.
53(2)
Any agreement relating to a protected shorthold tenancy (whether or not contained in the instrument creating the tenancy) shall be void in so far as it purports to impose any penalty or disability on the tenant in the event of his giving a notice under this section.