Indirect discrimination happens where there is less favourable treatment in effect or by impact. It happens where people are, for example, refused employment or training not explicitly on account of a discriminatory reason but because of a provision, practice or requirement which they find hard to satisfy. If the provision, practice or requirement puts people who belong to one of the grounds covered by the Acts at a particular disadvantage then the employer will have indirectly discriminated, unless the provision is objectively justified by a legitimate aim and the means of achieving that aim are appropriate and necessary.
Discrimination by association happens where a person associated with another person (belonging to a specified ground) is treated less favourably because of that association. Employers are liable for anything done by an employee in the course of his or her employment, unless the employer can prove that he or she took reasonably practicable steps to prevent the discrimination.
Section 22.1 of the Acts provides:
“(a) Indirect discrimination occurs where an apparently neutral provision puts persons of a particular gender at a particular disadvantage in respect of any matter other than remuneration compared with other employees of their employer.
(b) Where paragraph (a) applies, the employer shall be treated for the purposes of this Act as discriminating against each of the persons referred to, unless the provision is objectively justified by a legitimate aim and the means of achieving that aim are appropriate and necessary.”
Section 31 of the Acts has an identical provision in respect of other protected grounds.
In Bilka Kaufhaus GMBH v. Weber von Hartz  ECR 1607 the ECJ laid down a three tier test in determining whether the provision amounts to indirect discrimination.
Namely, a tribunal must assess whether the measures chosen by the employer:
(i) correspond to a real need on the part of the undertaking
(ii) are appropriate with a view to achieving the objectives pursued, and
(iii) are necessary to that end.
This case law is now encapsulated in Council Directive 97/80/EC. Pursuant to this provision, indirect discrimination is defined as: “where an apparently neutral provision, criterion or practice would put persons of one sex at a particular disadvantage compared with persons of another sex, unless that provision, criterion or practice is objectively justified by a legitimate aim, and the means of achieving that are appropriate and necessary.”
Once a prima facie case of indirect discrimination is established, it is then for the respondent to demonstrate that the provision or requirement is objectively justified by a legitimate aim and the means of achieving that aim are appropriate and necessary.