Sex and marital discrimination is unlawful under the Sex Discrimination Act (SDA):

Direct discrimination is less favourable treatment on grounds of the complainant's gender, which includes pregnancy and being on maternity leave, and being married or in a civil partnership. 

Indirect discrimination is where a provision, criterion or practice is applied to men and women: 

• which is such that it puts or would put women at a particular disadvantage when compared with men (or vice versa), or married people than single people, or people in a civil partnership than not,

• which is not a proportionate means of achieving a legitimate aim,

• which is to the complainant's disadvantage

 
This is where a practice has the effect of disadvantaging women compared to men (generally because of childcare or elder care responsibilities) and which cannot be justified by the employer. An example would be the refusal of part-time or other flexible working.

Victimisation is where a worker has been treated less favourably for alleging discrimination, bringing a claim, giving evidence or taking other action under the SDA.  It also covers the situation where the employer believes or suspects that the victim has done or intends to take such action.

Harassment is a treatment which either undermines dignity, is of an unwelcome sexual nature or creates an intimidating, hostile, degrading, humiliating or offensive environment; the conduct will be regarded as harassment if, having regard to all the circumstances, including in particular the complainant's perception, it should reasonably be considered as having that effect.

The SDA protects job applicants, workers, employees, ex-employees and others in relation to: recruitment, promotion, training, dismissal or any other disadvantage (such as distress).

Gender reassignment discrimination is unlawful where a worker is treated less favourably on the ground that the complainant intends to undergo, is undergoing or has undergone gender reassignment. It is discriminatory if an employee, who is absent from work to undergo gender reassignment, is treated less favourably than an employee whose absence is due to sickness.