'Prima facie' means 'on the face of it'. This means that (in the case of unlawful discrimination*) the individual has to reasonably show that discrimination might be occurring. Then the employer has to prove that it isn't.
* i.e. on the grounds of sex, race, age, disability, sexual orientation or religion/philosophical belief
cesare - please could you explain how someone shows discrimination on these grounds when employers have become adept at hiding discrimination ?
(I do know wouldn't be able to explain it as well legally except to say that if a person is treated differently in comparison to another employee, who is of a different gender, or race, then that is discrimination.)
One thing that is important to know is that a person can make a claim under discrimination law re race etc if they have only been employed for one day, whereas other claims you have to have been employed for a minimum of 12 months.

As VP says ... causal link.
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