3. The annual rate of an official pension may, if a qualifying condition is satisfied or the pension is a widow’s pension, be increased by the pension authority in respect of any period beginning on or after 11th April 1988 as follows—
(1) a pension beginning before 27th April 1987 may be increased by 4.2 per cent of the basic rate as increased by the amount of any increase under section 1 of the 1971 Act or the existing Orders;
(2) a pension beginning on or after 27th April 1987 and before 11th April 1988 may be increased by 4.2 per cent multiplied by whereB
(a)A is the number of complete months in the period between the beginning date of the pension and 11th April 1988, and
(b)B is 12.