Notwithstanding anything contained in section 22, where any premises which have been let comprise vacant land upon which it is permissible under the building regulations or municipal bye-laws, for the time being in force, to erect any building, whether for use as a residence or for any other purpose and the landlord proposing to erect such building is unable to obtain possession of the land from the tenant by agreement with him and the Rent Authority, on an application made to him in this behalf by the landlord, is satisfied that the landlord is ready and willing to commence the work and that the severance of the vacant land from the rest of the premises will not cause undue hardship to the tenant, the Rent Authority may--
         (a) direct such severance;
         (b) place the landlord in possession of the vacant land;
         (c) determine the rent payable by the tenant in respect of the rest of the premises; and
         (d) make such other order as he thinks fit in the circumstances of the case.