(1)If, in the case of a compulsory acquisition to which this Part of this Act applies, the appropriate authority is satisfied that the relevant land or some part thereof does not constitute or form part of the claim area of any established claim, but that a claim or claims in respect of one or more interests in that land, or, as the case may be, in that part thereof, would have been established if made, there shall be issued by or on behalf of the Treasury a certificate specifying—
(a)whether or not, in the opinion of the person signing the certificate, section thirty-one of this Act would have applied to the compulsory acquisition if the claim or claims aforesaid had been established; and
(b)if so, what in that person's opinion, after giving the person entitled to the relevant interest an opportunity to present his case, would have been the amount of the additional compensation calculated by reference to the unexpended balance of established development value of that land or that part thereof which would have been payable under that section in respect of the acquisition of the relevant interest.
(2)Where an amount has been specified as aforesaid that amount shall be added to the compensation payable in respect of the acquisition of the relevant interest apart from the provisions of this section:
Provided that if, after taking into account all the circumstances, the appropriate authority is of opinion that it is not just and reasonable that the whole of that amount should be so added or, as the case may be, that any amount should be so added, the said authority may direct that such lesser amount as he may specify shall be so added or, as the case may be, that no addition to the compensation aforesaid shall be made.
(3)In this section, the expression " the appropriate authority " means—
(a)where the compulsory acquisition of the relevant interest by the acquiring authority requires authorisation by a single other authority, that other authority; or
(b)where the acquiring authority is a government department and the compulsory acquisition does not require the authorisation of any other authority, the acquiring authority; or
(c)in any other, case, the Treasury or such other authority as the Treasury may in any case or class of cases direct.