4(1)An officer to whom this Schedule applies may be granted a pension—
(a)if he retires after not less than the prescribed number of years of relevant service and at the time of his retirement he has attained the age of 65, or
(b)if he retires after not less than 5 years relevant service, and—
(i)at the time of his retirement he has attained the age of 72, or
(ii)if the Minister is satisfied by means of a medical certificate that he is incapable from infirmity of mind or body of discharging the duties of his office and that the infirmity is likely to be permanent.
(2)In sub-paragraph (1)(a) above the prescribed number of years is—
(a)where the officer is the Lord Chancellor's Legal Visitor, 10 years,
(b)in any other case, 15 years.
(3)The annual rate of the pension payable under this paragraph to a person retiring after not less than 20 years relevant service shall not exceed one half of his last annual salary.
(4)The annual rate of the pension payable under this paragraph to a person retiring after less than 20 years relevant service shall not exceed—
(a)if the period of relevant service amounts to less than 10 years (but not less than 5), 15/80ths of his last annual salary plus 1/80th for each completed year of relevant service exceeding 5,
(b)if the period of relevant service amounts to not less than 10 years (but less than 20 years) one quarter of that salary plus 2/80ths for each completed year of relevant service after the first 10 years.