A lesbian teacher was called insulting terms like ‘dyke’. HL said this was not sex discrimination within s.1(1)(a) SDA. The question was whether a male comparator (i.e. a homosexual) would have been treated differently by the employer. Otherwise it could not be found that the reason for the harassment was gender based. On the facts there was no evidence that a homosexual employee would have been treated any differently. It was irrelevant that the taunts were gender specific (i.e. to lesbians).
Lord Nicholls: Sexual harassment under SDA is only possible where the reason for the harassment was because of the individual’s sex. The fact that the harassment takes form through gender-specific words or actions (e.g. calling her a dyke) does not mean that gender was the reason for the harassment. The reason for the abuse was sexuality, not sex.