The amount of compensation payable to the tenant under section 16 of this Act in respect of a tenant’s improvement which consists of planning permission shall be an amount equal to the increase attributable to the fact that the relevant development is authorised by the planning permission in the value of the holding at the termination of the tenancy as land comprised in a tenancy.
In subsection (1) above, “the relevant development” means the physical improvement or change of use specified in the landlord’s consent under section 18 of this Act in accordance with subsection (1)(b) of that section.
Where the landlord and the tenant have entered into an agreement in writing whereby any benefit is given or allowed to the tenant in consideration of the obtaining of planning permission by the tenant, the amount of compensation otherwise payable in respect of that permission shall be reduced by the proportion which the value of the benefit bears to the amount of the total cost of obtaining the permission.