Where an employer fails to take what the employee tells him seriously (or at face value) it may give rise to the employee making a claim for constructive dismissal.
Wigan Borough Council v Davies 1979. "There is an implied term in contracts of employment that the employer will provide reasonable support to ensure that the employee can carry out his/her duties without harassment or disruption by fellow workers; and where an employer has an obligation totake reasonable steps to achieve something and takes few or no steps, the onus of proving what steps would have been reasonable is on the employer."
An employer's failure to take "reasonable and practicable steps" to prevent the harasser from harassing the complainant may likely make the employer "vicariously liable" for the harasser/s acts pursuant to s.109 of the Equality Act 2010. This means that the employer could be "vicariously liable" for an employee's conduct, whether the employer knows harassment is happening or not. In our own case, we contended our employer was "vicariously liable" for "omitting to act" to take adequate "control measures" to 'prevent' further acts of harassment from being purported upon our persons. The fact our employer initiated an investigation into our grievances was not enough. Our employer could have, and should have acted immediately, and taken proactive and preventative measures to ensure that we were not subjected to any further acts of discrimination, harassment, less favourable treatment or victimisation.
Pursuant to s.110(1)(a)(b)(c)(2) of the Equality Act 2010, the harasser is personally liable for their own actions. Thus, most bully's do not realise that you can sue them too; this being in addition to your employer, for harassment! This is a very powerful tool. When I wrote my grievance letter to my employer, I held the Company vicariously liable pursuant to s.109(1)(2)(3)(4)(a)(b) of the Equality Act 2010, in addition to making my line manager personally liable for her own actions under s.110 of the Equality Act 2010.
I can tell you, nothing puts the fear of God into a bully when they are personally served with an Employment Tribunal claim pursuant to s.110(1)(a)(b)(c)(2) and s.112(1) of the EqA 2010! Moreover, if some other person aids, induces or causes harassment / discrimination, that person can also be held to account pursuant to s.111 of the Equality Act 2010. This is really useful when you have a group of bullies who egg each other on (google workplace mobbing).
Notwithstanding, our employer had failed to observe the mutual trust and confidence by failing to demonstrate "adequate prevention methods" to eradicate harassment from reoccurring. It had 'omitted to act' to render any training, consultations or advice to its employees. Despite the fact our employer had a harassment policy insitu, it had failed to "implement" its policies and procedures within the workforce at large. It is not enough for an employer to rely upon the fact it has a Harassment Policy. The employers Harassment Policy has to be "effectual" and "effectively communicated" to all its employees - See: Beadles Group Ltd v Angelica Graham. Also, see "fiduciary obligations".
Bracebridge Engineering Ltd v Darby  IRLR 3 EAT
A single act of harassment if it is sufficiently serious will be unlawful discrimination.
Canniffe v East Riding of Yorkshire Council  IRLR 555, EAT
The existence of an employer's formal policy against sex harassment is not necessarily enough on its own to amount to an adequate defence against a sex discrimination claim by an employee arising from sex harassment. To havea valid defence, an employer must prove that it took such steps as were reasonably practicable to prevent the employee from doing the sex discriminatory act. Therefore if the employer has not taken such steps, it cannot escape liability by showing that the discriminatory act would have taken place even if it had taken them.
Beadles Group Ltd v Angelica Graham
The employer had no written policy on either sex discrimination/harassment, or equal opportunities, and did not provide training or advice to ordinary employees about sexual harassment, or warn them against it. Ms Graham was awarded £180,000
Reed v Steadman  IRLR 299
The Employment Appeal Tribunal held that, in relation to sexual harassment, the issue is whether "the words or conduct [are] unwelcome to the victim and it is for her to decide what is acceptable or offensive. The question is not what (objectively) the employer/tribunal would or would not find offensive."
Fletcher and Steele v Cannon Hygiene Ltd
A failure by an employer to separate two women from their female harasser amounted to harassment. The employer failed to take sufficient steps to protect them from further sex harassment. This case takes into account the European Commission Code of Practice on Sex Harassment 1991 to separate the victim from the alleged harasser.
Insitu Cleaning Co Ltd v Heads  IRLR 4
The EAT held that a 'sexual remark' was discriminatory. Mrs. Heads was greeted in a meeting by the words "Hiya, big tits". She found the remark "very embarrassing" and "distressing". The tribunal found that the remark was sufficiently serious to constitute a "detriment" for which her employer's were "vicariously liable".
For in depth information, see Here