51.—(1) Where an improvement notice is served and, within one month, the landlord serves an improvement undertaking and no superior landlord serves an improvement objection the tenant may, by notice in writing served on the landlord within fourteen days after the service of the undertaking, either accept it or withdraw the improvement notice or, where the undertaking specifies an increase of rent, object to its amount.

(2) Where the tenant does not serve a notice under subsection (1) or accepts under that subsection the improvement undertaking, the landlord shall, as soon as may be, and in any case not later than six months after the expiration of such fourteen days, execute and complete at his own expense and in accordance with the improvement undertaking the improvement mentioned therein and may for that purpose enter on the tenement at all reasonable times and there do all things necessary for or incidental to the execution of the improvement.

(3) If the tenant withdraws the improvement notice, that notice shall be deemed never to have been served.

(4) Where the tenant objects to the amount of the increase of rent specified in the improvement undertaking, then—

(a) the landlord and the tenant may either fix by agreement the amount of the increase of rent or agree that its amount shall be fixed by the Court, and thereupon the improvement undertaking shall have effect in accordance with that agreement and be deemed to have been duly accepted by the tenant, or

(b) either the landlord or the tenant may apply to the Court and, upon the hearing of the application, the Court may, as it thinks proper, either fix the amount of the increase of rent or deem the improvement undertaking to be an improvement objection and deal with it accordingly or make such other order as justice may require.

(5) Where the improvement undertaking is, by its terms or by subsequent agreement, made subject to an increase of rent of an amount to be fixed by the Court, the landlord or the tenant may, when the improvement has been duly executed by the landlord, apply to the Court to fix the amount of the increase of rent.

(6) Upon the completion of the improvement by the landlord in accordance with the improvement undertaking and this section, the rent payable by the tenant to the landlord shall, from the date of completion, be increased in accordance with the undertaking or the order of the Court (as the case may be), and any dispute as to the amount or commencement of or otherwise in relation to the increase shall be determined by the Court on the application of the landlord or the tenant.

(7) Where the landlord is bound under this section to execute the improvement in accordance with the improvement undertaking but refuses or fails to execute and complete it within the time limited in that behalf by this section, the tenant may apply to the Court and the Court may make such order in the matter as justice may require.