Where any premises in respect of which a demolition or closing order or a clearance order has become operative form the subject matter of a lease, either the lessor or the lessee may apply to the county court within the jurisdiction of which the premises are situate for an order under this section:

Provided that this subsection shall not apply to a closing order made under section eighteen of this Act.

Upon any such application as aforesaid, the county court judge, after giving to any sub-lessee an opportunity of being heard, may, if he thinks fit, make an order for the determination of the lease, or for the variation thereof, and, in either case, either unconditionally or subject to such terms and conditions (including conditions with respect to the payment of money by any party to the proceedings to any other party thereto by way of compensation, damages, or otherwise) as he may think just and equitable to impose, regard being had to the respective rights, obligations, and liabilities of the parties under the lease and all the other circumstances of the case.

In this section the expression " lease " includes an underlease and any tenancy or agreement for a lease, under-lease, or tenancy, and the expressions " lessor," " lessee," and " sub-lessee " shall be construed accordingly, and as including also a person deriving title under a lessor, lessee or sub-lessee.