4.—(1) A person shall be treated for the purposes ofparagraph 1 above as having been ordinarily resident in the BritishIslands throughout the three years preceding the relevant date if he isa British citizen within the meaning of the British Nationality Act1981(1) and—
(a)he was not so resident only because he was ordinarily resident forthe purposes of employment in the European Community during every partof that period in which he was not ordinarily resident in the BritishIslands; or
(b)(i)he was not so resident throughout that period only becausehis parent is such a person as is mentioned in sub-paragraph (a), and
(ii)his parent is ordinarily resident in Great Britain on the relevant day.
(2) In sub-paragraph (1) above“parent” includes a guardian and any other person having actual custody of aminor, and“relevant day” means—
(i)where the person had entered the United Kingdom before the dayone month earlier than that of the beginning of the term in which hecommences his course, that day;
(ii)where he had not so entered the United Kingdom, the day of thebeginning of that term.