any compensation which is payable under this Act in respect of the depreciation in value of that interest shall be calculated as if the interest were not subject to the mortgage;

a claim for the payment of any such compensation may be made by any mortgagee of the interest under a mortgage made before the happening of the event giving rise to the compensation, but without prejudice to the making of a claim by any other person;

a mortgagee shall not be entitled to claim any such compensation in respect of his interest as such; and

any such compensation payable in respect of the interest subject to the mortgage shall be paid to the mortgagee or, where there is more than one mortgagee, to the first mortgagee, and shall in either case be applied by him as if it were proceeds of sale.