The vast majority of employers have no idea where the line lies between office jokes and harassment, according to research.
Eighty three per cent of the 1,894 employers polled by law firm Peninsula said they were unaware of the point in law where a joke becomes harassment.
This was despite two-thirds of managers admitting they witnessed workplace pranks escalating to the point where it offended staff.
Employees reflected this indecision, with only 18% saying they had had a complaint about offensive jokes taken seriously by your employer.
Mike Huss, senior employment law specialist, Peninsula, explained the legal position in relation to harassment.
"In the Protection from Harassment Act 1997, it states a person must not pursue a course of conduct which amounts to harassment of another in which he knows or ought to know amounts to harassment of another.
"The person who's course of conduct in question should be aware that their conduct amounts to harassment of another, on the basis that a reasonable person with the same information would come to the conclusion that the conduct amounted to harassment," he said.
An employer is also under a general duty of care under the Health and Safety at Work Act 1974 to ensure the welfare of employees.