For my records:
Exclusion of discrimination on particular grounds in certain employments.
37.—(1) A religious, educational or medical institution which is under the direction or control of a body established for religious purposes or whose objectives include the provision of services in an environment which promotes certain religious values shall not be taken to discriminate against a person for the purposes of this Part or Part II if—
(a) it gives more favourable treatment, on the religion ground, to an employee or a prospective employee over that person where it is reasonable to do so in order to maintain the religious ethos of the institution, or
(b) it takes action which is reasonably necessary to prevent an employee or a prospective employee from undermining the religious ethos of the institution.