(1) Subject to sub-article (2), an optional contribution payable in respect of any contribution year (including a contribution payable in instalments under article 46) shall be paid to the Minister before the end of that contribution year.

(2) Where a person who, having become an optional contributor within the three months before the end of a contribution year, pays an optional contribution in respect of that contribution year not later than three months following the last day of the said contribution year, the optional contribution so paid shall be treated as having been paid before the end of the contribution year to which it relates.

(3) An optional contribution which is not paid in accordance with the provisions of this article shall be treated as not having been paid.