If you are a worker and you have tried solving a problem or concern informally by talking to your manager but you are not satisfied, you can make a formal grievance complaint in writing.
Your employer should have a written grievance procedure that tells you what to do and what happens at each stage of the process. After raising the grievance you will have a meeting to discuss the issue.
You can appeal if you do not agree with your employer’s decision.
Mediation can also help resolve a problem - this can take place at any time during the dispute.
Following the Acas code of practice
You and your employer should follow the Acas code of practice on disciplinary and grievance procedures.
Otherwise, if you take your claim to an employment tribunal, any compensation you might get could be adjusted by up to 25%.
Further information on Grievances at work can be found on GOV.UK's website.