Where a rent (in this paragraph referred to as the first rent) for a dwelling-house which is subject to a regulated tenancy has been registered as mentioned in paragraph 1 of this Schedule and, in any year of the period of delay imposed by paragraph 2 of this Schedule, a new rent for the dwelling-house is registered under Part IV of the Act of 1971, then, if the new rent exceeds the rent for the time being recoverable under the regulated tenancy, the following provisions of this paragraph shall apply and the foregoing provisions of this Schedule shall not apply.

The rent for any statutory period beginning before the end of the period of delay shall not be increased by a notice of increase under section 21(2)(b) of the Act of 1971 except to the extent permitted by the following provisions of this paragraph ; and any such notice which purports to increase it further shall have effect to increase it to the extent so permitted but no further.

If the new rent is less than the first rent, the rent payable under the regulated tenancy may be increased (up to the amount registered) to the same extent as if the first rent had remained registered.

If the new rent exceeds the first rent, the rent payable for any statutory period beginning after the date of registration may be increased by the difference between the first rent and the new rent, but, apart from that increase, the amount to which the rent may be increased thereafter (up to the new rent) is to be determined as if the first rent had remained registered.