52.—(1) Subject to paragraph (2), no increase under Article 51 is required to be paid to or for a member of a scheme whose pension is in payment but who has not attained the age of 55 at the time when the increase takes effect.
(2) Paragraph (1) does not apply if the member—
(a)is permanently incapacitated by mental or physical infirmity from engaging in regular full-time employment, or
(b)has retired on account of mental or physical infirmity from the employment in respect of which, or on retirement from which, the pension is payable.
(3) The rules of a scheme may provide that if, in a case where a pension has been paid to or for a member under the age of 55 at an increased rate in consequence of paragraph (2), the member—
(a)ceases to suffer from the infirmity in question before he attains the age of 55, but
(b)continues to be entitled to the pension,
any increases subsequently taking effect under Article 51 in the annual rate of the pension shall not be paid or shall not be paid in full.
(4) In any case where—
(a)by virtue only of paragraph (1) or (3), increases are not paid to or for a member or are not paid in full, but
(b)the member attains the age of 55 or, in a case falling within paragraph (3), again satisfies the condition set out in paragraph (2)(a) or (b),
his pension shall then become payable at the annual rate at which it would have been payable apart from paragraph (1) or (3).