1. QT is a British national. She is homosexual and met her partner, SS, who has dual South African and British nationality, in 2004. In May 2011, QT and SS entered into a same-sex civil partnership in England under the UK’s Civil Partnership Act 2004. 2. SS was offered employment in Hong Kong and granted an employment visa to come and work here. On 23 September 2011, the couple entered Hong Kong, SS on the strength of her employment visa and QT as a visitor. 3. After making unsuccessful applications for a dependant visa and also for an employment visa in her own right, on 29 January 2014 QT submitted the application for a dependant visa which is the subject of this judicial review. 4. On 18 June 2014, the Director of Immigration (“the Director”) refused her application. He found QT ineligible to be considered for the dependant visa given that she was “outside the existing policy” which was to admit a spouse as a dependant only if he or she was party to a monogamous marriage consisting of one male and one female (the “Policy”). The Courts below 5. In October 2014, QT commenced the present judicial review proceedings seeking to quash the Director’s decision refusing her dependant visa application, arguing, among other things, that the Director’s decision was unreasonable in the public law sense as it was discriminatory against her on sexual orientation grounds that were not justified. 6. In the Court of First Instance, QT’s application for judicial review was dismissed. However, the Court of Appeal unanimously allowed QT’s appeal. It held that the sexual orientation discrimination ground was decisive of the appeal. 7. The Director’s stated rationale for adopting the Policy was (a) to encourage persons with needed skills and talent to join Hong Kong’s workforce, accompanied by their dependants; and (b) to maintain a system of effective and stringent immigration control. The Director argued that he was entitled to draw a “bright line” between married and unmarried persons, for the sake of legal certainty and administrative convenience. (the “Director’s Justification”) 8. The Court of Appeal held that whilst the aims of attracting talent and immigration control were legitimate, the Director’s eligibility requirement, restricted to heterosexual married persons and excluding same-sex married partners or civil partners, was not rationally connected to those aims. 9. The CA gave permission for the Director to appeal to this Court. Fifteen banks, sixteen law firms, and Amnesty International applied for permission to intervene and make submissions, but their applications were refused. This Court’s analysis 10. The Director has wide powers over immigration control under the Basic Law and the Immigration Ordinance pursuant to which the Policy is operated. However, the Director rightly accepted that he must exercise them in accordance with the principle of equality. The rule of law requires such powers to be fairly and rationally exercised and the principle of equality (treating like cases alike and unlike cases differently) is an important aspect of such rationality. Violation of this principle may lead to a successful judicial review challenge. 11. The two main contested issues were (i) whether there was a differential treatment of QT which was discriminatory; and (ii) if so, whether such discriminatory treatment could be justified. 12. It should be noted that this appeal does not involve any claim that same-sex couples have a right to marry under Hong Kong law, and that it was recognised that a valid marriage under Hong Kong law is heterosexual and monogamous and is not a status open to couples of the same sex. Is justification required? 13. The Director’s first argument was that the differential treatment between QT and a married spouse under the Policy requires no justification, since an obvious difference exists between a partner to a civil partnership and a married spouse. He argued that he was entitled to adopt a policy conferring the benefit of a dependant visa only on spouses in a union which, if celebrated here, would have been recognised as a valid marriage under Hong Kong law. Thus, it was argued that he was entitled to treat same-sex couples who could not attain marital status under Hong Kong law as being obviously not in a relevantly similar situation with married couples. 14. The Court rejected this argument for three reasons. First, it is circular. It puts forward the challenged differentiating criterion as its own justification. To the question: “Why is QT treated less favourably than a married person?” he essentially answers: “Because she is not married”. Secondly, the Director’s assertion that an obvious difference exists between marriage and a civil partnership was not accepted. Marriage and civil partnership are each a status recognised under United Kingdom law. Civil partnership is not called marriage but in almost every other respect it is indistinguishable from the status of marriage. Thirdly, the decided cases cited by the Director do not support his argument. 15. The Court of Appeal in the present case suggested that there are certain “core rights and obligations” unique to marriage based on which differential treatment cannot be regarded as discriminatory and therefore requires no justification. Such an approach is also circular and gives rise to fruitless debates as to what does or does not fall within the “core”. It should not be followed. The correct approach is to examine every alleged case of discrimination to see if the difference in treatment can be justified. The Director’s Justification 16. It was accepted by the Director that if the differential treatment required justification, the Policy would involve indirect discrimination on the basis of sexual orientation since same-sex couples would not be able to enter into a marriage valid under Hong Kong law to satisfy the eligibility requirements. The Director argued, however, that the differential treatment was justified and that the court should not interfere unless it found that the Policy was manifestly without reasonable foundation. 17. The Court agreed with the Court of Appeal in holding that there was no rational connection between the Policy and the stated twin aims of attracting foreign talent and maintaining strict immigration control. The Policy ran counter to the aim of encouraging talent to join the Hong Kong workforce since a person who had the talent or skills deemed needed or desirable could be straight or gay. It is similarly hard to see how the Policy’s exclusion, on grounds of sexual orientation, of persons who were bona fide dependant civil partners of sponsors granted employment visas promoted the legitimate aim of strict immigration control. 18. The differential treatment of QT on the basis of administrative convenience was also irrational given that QT and SS could just as conveniently produce their civil partnership certificate as a heterosexual married couple could produce their marriage certificate. 19. In the absence of a rational connection between the Policy and the avowed legitimate aims, it was not necessary to determine whether the differential treatment was proportionate to accomplishing those aims. The appropriate standard of review is case-specific and the Court would, if necessary, have examined whether the Policy went beyond what was reasonably necessary to attain aims which were legitimate. Disposition 20. The appeal was unanimously dismissed.