(1) Where payment of retirement benefit has commenced and where the retirement benefit paid in pension form is increased (or would be increased if it were still in payment) by a cost of living increase under the rules in force (whether by way of exercise of discretion or otherwise) the designated benefit which is payable in pension form shall be increased at the same rate or in the same manner.
(2) In this article 36 "cost of living increase" means an increase in the pensions payable to or in respect of all members of the pension scheme, or to or in respect of a category of members of the pension scheme, which is designed to take account of an increase in the cost of living or a reduction in the purchasing power of pensions.