Is an employee required to submit an appeal against the outcome of a grievance in writing?

The Acas code of practice on disciplinary and grievance procedures provides that an employee who is dissatisfied with the outcome of a grievance should appeal and provide the grounds for appeal in writing. If an employee raises an appeal verbally, the employer should ask the employee to put the grounds for appeal in writing.

If the employee refuses to submit the grounds in writing, the employer would be advised still to hear the appeal and notify the employee of the outcome without unreasonable delay. Should the grievance become relevant to subsequent tribunal proceedings, and if the employee is successful with their claim, the tribunal could make a reduction to any compensation that it awards of up to 25% if it considers that the employee unreasonably failed to comply with the Acas code by not providing the written grounds for their grievance appeal.