(1)  Where an order for eviction in respect of any premises is made under section 14 against a tenant but not against a sub-tenant referred to in section 17 and a notice of the sub-tenancy has been given to the landlord, the sub-tenant shall, with effect from the date of the order, be deemed to become a tenant holding directly under the landlord in respect of the premises in his occupation on the same terms and conditions on which the tenant would have held from the landlord, if the tenancy had continued.

   (2)  Where, before the commencement of this Act, the interest of a tenant in respect of any premises has been determined without determining the interest of any sub-tenant to whom the premises either in whole or in part had been lawfully sub-let, the sub-tenant shall, with effect from the date of the commencement of this Act, be deemed to have become a tenant holding directly under the landlord on the same terms and conditions on which the tenant would have held from the landlord, if the tenancy had continued.