Harassment is where someone’s dignity is violated, or they suffer an intimidating, hostile, degrading, humiliating or offensive environment. Harassment on the basis of someone’s protected characteristic (eg sex, race or disability) is prohibited by the Equality Act 2010.
Many organisations now specify in their employee rules that the circulation of materials in the workplace that could cause offence, will be regarded as misconduct.
If things don’t improve then you should follow your organisation's grievance procedure, or its procedure for harassment complaints, if it has one. You have a legal right to be accompanied by a work colleague or a trade union official to the hearing of your grievance. You will need to support your case by providing specific instances of where you feel harassment has taken place, so you should keep a record of examples, and when they occurred.
If you can’t sort things out with your employer you can present an unlawful discrimination claim to an employment tribunal. Claims should be made as soon as possible, but in any event no more than 3 months after the act you are complaining about. If you have raised the issue on several occasions but the discrimination is still continuing, the time limits will begin from the date of your last complaint.