Examples
A female employee thinks she is underpaid compared with a male colleague. She asks him what he is paid, and he tells her. The employer takes disciplinary action against the man as a result. The man can bring a claim for victimisation against the employer for disciplining him.
A female employee who discloses her pay to one of her employer’s competitors with a view to getting a better offer could be in breach of a confidentiality clause in her contract. The employer could take action against her in relation to that breach.