The landlord may vary the rent payable under a periodic standard contract by giving the contract-holder a notice setting out a new rent to take effect on the date specified in the notice.
The period between the day on which the notice is given to the contract-holder and the specified date may not be less than two months.
Subject to that—
the first notice may specify any date, and
subsequent notices must specify a date which is not less than one year after the last date on which a new rent took effect.
This section is a fundamental provision which is incorporated as a term of all periodic standard contracts under which rent is payable, except a periodic standard contract which is a housing association tenancy.