Formal vs informal grievance: when to escalate

An informal grievance is a concern an employee raises directly with a manager, usually in conversation, without invoking the written grievance procedure. A formal grievance is a written complaint submitted through that procedure, which brings an investigation, a grievance meeting, a written outcome, and the right to appeal. This guide describes UK practice under the Acas Code of Practice.

Acas research puts the annual cost of formal disciplinary and grievance procedures at £2.36 billion across UK employers, against roughly £250 million for resolving concerns informally. That tenfold gap is the whole argument for informal resolution wherever it genuinely fits. Treating a serious issue as informal because it is cheaper and faster is the kind of decision that looks bad in front of a tribunal.

What makes a grievance formal or informal?

The meaning of "formal grievance" has nothing to do with how serious the issue feels to the employee. It is about which process you use. A minor issue raised formally still gets the formal process. A serious issue raised in a hallway conversation is still, technically, informal, until someone puts it in writing.

When to raise a formal grievance

Acas sets out three situations where an employee should move to a formal grievance:

• an informal conversation has not resolved the issue
• they do not want to raise the matter informally at all
• the issue is serious enough that informal resolution is not appropriate, such as sexual harassment or whistleblowing

There is no obligation to try informal resolution first if the situation does not call for it. Acas pushes informal resolution as the default starting point, not as a mandatory first step. For how these categories usually get classified, see our overview of the types of grievances in the workplace.

The informal grievance procedure

An informal grievance procedure is less a fixed process than a conversation, typically between the employee and their manager, aimed at resolving the issue without paperwork or a formal investigation. Employees have no statutory right to bring a companion to this conversation, though many employers allow it as good practice. If the conversation resolves things, the employer should still confirm in writing what was discussed and agreed, so there is a record if the same issue resurfaces.

Do you have to document an informal grievance?

There is no legal requirement to create a formal written record of every informal conversation. A brief note of what was raised, what was discussed, and what was agreed protects both sides if the issue comes back. It is also the difference between an employer who can show a pattern of responsiveness and one who cannot.

When should a grievance become formal?

A grievance should move from informal to formal when the informal conversation has not worked, when the employee decides they want the formal process, or when a manager recognizes the issue was too serious to handle informally in the first place. No set number of informal attempts is required before escalation. One unresolved conversation is enough justification to formalize a grievance.

Where mediation fits alongside a formal grievance

Mediation is not simply the informal alternative to a formal grievance. In mediation, an independent and impartial person works with both sides to find a resolution they both agree to, and it can run alongside a formal procedure rather than instead of one. An employee can raise a formal grievance and still agree to try mediation before or during the investigation, including once the case has reached the grievance meeting stage. Both sides have to agree to it, and the mediator can come from inside or outside the organization.

Drawing the line the same way across the business

The line between informal and formal often gets drawn differently depending on which manager is handling the case. One treats a written email as an informal heads-up. Another treats the same email as a formal grievance, because that is how it happened to land in their inbox.

With SpeakUp Report, every case carries a clear status from the moment it is logged, so the distinction between informal and formal does not rest on an individual judgment call each time. Read the full grievance procedure, step by step, or see how the HR grievance software supports both routes.

Frequently asked questions

What is the difference between a formal and informal grievance?

An informal grievance is a concern raised directly with a manager, usually in conversation, without triggering the written grievance procedure. A formal grievance is a written complaint submitted through that procedure, which brings a formal investigation, a grievance meeting, a written outcome, and the right to appeal.

When should a grievance become formal?

When an informal conversation has not resolved the issue, when the employee does not want to raise it informally in the first place, or when the issue is serious enough, such as harassment or whistleblowing, that informal resolution is not appropriate from the start.

Do you have to document an informal grievance?

Not legally, but it is good practice. A short written note of what was discussed and agreed protects both employer and employee if the same issue comes up again, and gives HR a record to point to if the case is later escalated.