15Invalidity pension
On a review under section 125 of the [1975 c. 14.] Social Security Act 1975 (duty to increase rate of benefits) made in June 1985 subsection (3) of that section shall have effect as if at the end of it there were added the words " and also adding—
(a)to the rate of invalidity pension payable under any provision of this Act or the Pensions Act;
(b)to any increase in the rate of invalidity pension which is payable in respect of an adult dependant;
(c)to the amount of unemployability supplement; and
(d)to the rate of a disablement pension where the beneficiary is entitled to an increase under section 66(1) above,
an additional sum equal to the difference between—
(i)the sum that would have resulted from the review; and
(ii)the sum that would have resulted but for section 1 of the [1980 c. 39.] Social Security (No. 2) Act 1980 ".