4.—(1) The rate of the person’s state pension under section 7 is to be increased under this paragraph if, when added to the amount of any state pension that has priority, it is equal to or less than the full rate of the state pension.
(2) If at any time the full rate is increased, the rate of the person’s state pension under section 7 is increased (at that time) by the same percentage as the increase in the full rate.