s 4B Indirect discrimination on the ground of gender reassignment
(1) A person (“A”) discriminates against another person (“B”) in any circumstances relevant for the purposes of — (a) any provision of Part 3; or (b) any provision of Part 4, so far as it applies to vocational training, if A applies to B a provision, criterion or practice which is discriminatory in relation to B’s gender reassignment. (2) For the purposes of paragraph (1), a provision, criterion or practice is discriminatory in relation to B’s gender reassignment if— (a) A applies, or would apply, it to persons who do not intend to undergo, are not undergoing or have not undergone gender reassignment; (b) it puts, or would put, persons who intend to undergo, are undergoing or have undergone gender reassignment at a particular disadvantage when compared with persons who do not intend to undergo, are not undergoing or have not undergone gender reassignment; (c) it puts, or would put, B at that disadvantage; and (d) A cannot show it to be a proportionate means of achieving a legitimate aim.