What Evidence Do I Need for a Workplace Grievance?

Start with a clear account and relevant supporting material

You do not need a complete legal case before raising a workplace grievance. Start with an accurate account of the problem and identify relevant messages, documents, records and people who may help establish the facts. Explain what each item supports and where information is missing. The employer’s investigation can involve gathering evidence you do not hold.

There is no universal number of screenshots or witnesses that makes a grievance valid. Relevance, context and reliability matter more than volume. A small set of well-explained records is easier to assess than a large attachment folder with no indication of how the files relate to the complaint.

Match the evidence to the allegation

Break the complaint into specific issues, then ask what information could help check each one. A complaint about unequal shifts may need rotas and allocation criteria. A complaint about personal remarks may rely on your account, relevant messages and people who heard the conversation. Avoid collecting material simply because it concerns the person involved.

For example, if you say a deadline was changed after work had already been completed, the original instruction and later change are central. A colleague’s unrelated disagreement with the manager is not automatically evidence of that change. Keep the complaint focused so the investigator understands what needs to be established.

Use different kinds of evidence carefully

Your account is part of the information available, including where no one else witnessed the event. Contemporaneous notes can show what you recorded at the time, while later notes should be identified as retrospective. Neither should be described as an independently verified account unless that is actually true.

Treat these as different pieces of a picture rather than interchangeable proof. If a document is ambiguous, explain the question it raises. An honest limitation helps the reader use the material properly.

• Messages and emails can show wording, timing and participants; keep relevant context.
• Work records can show allocations, attendance or changes, but may not explain the motive.
• Witnesses can describe what they personally observed or know.
• Policies can show the expected procedure, but a policy breach does not automatically decide a legal claim.
• Health information may explain impact or support needs, without proving who caused every symptom.

Create a simple evidence index

Number the items and give each a short title, date and source. Add one sentence saying which incident it relates to and what it shows. If you refer to a long document, identify the relevant page or part while retaining enough context for a fair reading.

For example: item 04, email thread dated 11 to 13 October, showing the first deadline and the revised instruction. Keep file names consistent with the index. Avoid labels such as final proof of bullying, which state a conclusion rather than describe the document.

Identify records held by the employer

You may know that a relevant record exists without being able to obtain it yourself. Identify it precisely and ask the investigator to preserve and review it. A specific date, time, channel, task reference or location makes the request easier to action than asking for all records about a manager.

Act promptly where material may be deleted or overwritten. Do not assume a grievance automatically preserves every system record. Keep your request and any reply. If the record is unavailable, ask for an explanation rather than inventing what it would have shown.

Avoid creating new confidentiality problems

Use information you are entitled to access and retain. Do not enter someone else’s account, remove unrelated files or forward an entire company mailbox. If the material contains confidential information about customers or colleagues, ask how to supply the relevant part appropriately.

Keep originals unchanged. Label redacted or annotated versions and explain what has been removed. Avoid circulating allegations or sensitive documents among colleagues to gather support. Witnesses should give their own accounts, not an agreed version developed in a group discussion.

Include information that challenges your account

An investigation should consider both sides. If a message appears to contradict your recollection, keep it and explain the uncertainty. You may have misunderstood an instruction or discovered a date error. Correcting the record is better than omitting material that another person will later produce.

This does not mean you have to investigate against yourself or accept every explanation. It means giving an accurate account of the available information. A representative can help you distinguish a factual disagreement from a missing document or a different interpretation of the same event.

Submit a manageable pack and keep a copy

Send the grievance, a concise timeline and the evidence index through the appropriate channel. Ask how large or sensitive files should be supplied. Keep the version you submitted and a list of anything you are asking the employer to obtain. Update the handler with genuinely new material rather than repeatedly resending the full bundle.

If legal action is a possibility, check deadlines while the evidence is being gathered. An unfinished pack is not a reason to delay advice. A grievance process is different from tribunal disclosure, and obtaining more material does not automatically extend the time available to bring a claim.

Frequently asked questions

Can I raise a grievance with only my account? Yes. Be specific and identify any records or people the employer can check. Lack of witnesses does not by itself prevent a complaint.

Should I attach my entire medical record? Usually only relevant information should be considered. Ask what is needed to explain impact or adjustments and get advice before sharing unnecessary sensitive material.

Can I edit screenshots to make them clearer? Preserve the original. If you make a labelled copy for readability or redaction, explain the change and retain enough context to avoid a misleading impression.

Sources and scope

Guidance checked on 25 October 2026. This article covers England, Wales and Scotland. Northern Ireland has different employment laws and procedures; check the Labour Relations Agency guidance. Examples are fictional. Laws and procedures can change, so check the linked guidance and get advice about your circumstances.

• Acas: investigations and evidence
• GOV.UK: raising grievances
• Acas: gathering and considering evidence
• Acas: current tribunal time limits
• Northern Ireland: Labour Relations Agency

Dealing with something similar at work?

EviDiary helps you organise workplace incidents, notes and supporting evidence into a dated timeline. You can prepare a report using the features available on your plan. Start with the facts you remember and label any uncertainty; a diary does not independently verify an allegation or guarantee a legal outcome. EviDiary helps you document what happened and does not replace independent legal advice.

• Open EviDiary and start documenting
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