26E+WWhere any increase in the rent recoverable under a controlled tenancy current on 6th July 1957 took effect before that date but after the beginning of the basic rental period (within the meaning of Part II of this Act), section 27 of this Act shall have effect as if for references to the rent recoverable for the basic rental period there were substituted references to the rent which would have been recoverable for that period if the increase had taken effect before the beginning thereof.