This section applies to any complaint presented under section 63 to an employment tribunal.
Where, on the hearing of the complaint, the complainant proves facts from which the tribunal could, apart from this section, conclude in the absence of an adequate explanation that the respondent—
has committed an act of discrimination or harassment against the complainant which is unlawful by virtue of Part 2 or section 35A or 35B , or
is by virtue of section 41 or 42 to be treated as having committed such an act of discrimination or harassment against the complainant,
the tribunal shall uphold the complaint unless the respondent proves that he did not commit, or, as the case may be, is not to be treated as having committed, that act.