Sch 9 para 3
A person (A) with an ethos based on religion or belief does not contravene a provision mentioned in paragraph 1(2) by applying in relation to work a requirement to be of a particular religion or belief if A shows that, having regard to that ethos and to the nature or context of the work— (a) it is an occupational requirement, (b) the application of the requirement is a proportionate means of achieving a legitimate aim, and (c) the person to whom A applies the requirement does not meet it (or A has reasonable grounds for not being satisfied that the person meets it).