Can The Same Person Conduct Both Investigation and Disciplinary Proceedings? A Guide for UK Employers

If you’re a UK employer dealing with allegations of misconduct or performance issues at work, you may find yourself asking: can the same person do investigation and disciplinary? It’s a perfectly reasonable question-especially if you run a small business where resources are tight, and staff often wear multiple hats. Understanding where the lines should be drawn is key to keeping your disciplinary process fair, legal, and robust against challenge.

In this guide, we’ll demystify best practices around internal investigations and disciplinary hearings. We’ll look at whether splitting the roles is a legal must, what the risks are if you don’t, and practical steps you should follow whatever your company’s size. Whether you’re new to disciplinary procedures or want to future-proof your processes, keep reading to get clear, actionable advice.

Why Does the Division Between Investigation and Disciplinary Matter?

Before jumping into the details, let’s set the scene. When concerns are raised about an employee-whether it’s alleged misconduct, breaches of policy, or poor performance-UK employers are expected to follow a fair and thorough process. This typically involves two key stages:

• Investigation stage: Fact-finding to understand what happened and gather evidence.
• Disciplinary hearing: Deciding (based on the evidence) if disciplinary action is appropriate, and if so, which sanction to apply.

The fairness and independence of these stages are essential. Both the ACAS Code of Practice on Disciplinary and Grievance Procedures (widely referenced in UK employment tribunals) and case law stress the need for an unbiased, well-documented process. Getting it wrong can lead to tribunal claims for unfair dismissal-even if the underlying conduct justified a sanction.

Is It Legal For The Same Person To Do Both Investigation and Disciplinary?

This is one of the questions we hear most from small business owners: “Can the same person do investigation and disciplinary in my company?” In short: it’s not illegal or automatically unfair for one person to perform both roles, but there are risks, and best practice is to keep them separate where possible.

The ACAS Code doesn’t explicitly prohibit one person from investigating and chairing the hearing-especially if your business is small, and staffing makes this difficult. However, the Code and subsequent tribunal judgments make it clear:

• You should keep the process as impartial as possible.
• Where feasible, the investigator and the decision-maker at the disciplinary hearing should be different people.
• If that’s not possible, you must demonstrate that your process is still fair and unbiased.

For larger businesses, failing to separate the roles could well be seen as a departure from best practice, and could increase the likelihood of an unfair dismissal finding. For smaller companies with limited people, tribunals will take into account your constraints-but you’re still expected to do everything you reasonably can to ensure objectivity (read more on fair dismissal here ).

What Are The Risks If The Same Person Does Both Roles?

If one person investigates and also decides on discipline, the biggest risk is a perception of bias-or worse, an actual unfair process. Why?

• Predetermination: If the person who collected the facts also decides the outcome, there’s a danger they’ll unconsciously stick to their first impressions.
• Lack of independence: It’s harder to argue the hearing was impartial if the ‘judge’ has already played the role of ‘detective’.
• Unfair dismissal risk: Even technically correct decisions might be challenged if the employee can show the procedure wasn’t fair or independent.
• Breach of procedure: Not following clear, fair steps may breach your own disciplinary policy or employee contract.

Remember, employment tribunals often look at the overall fairness, including things like:

• Was the case thoroughly investigated?
• Did the employee have a fair chance to present their side?
• Was the decision fair and reasonable based on the evidence available at the time?
• Would a reasonable employer, acting reasonably, have done the same?

If one person does it all, you’ll need to show (with a clear paper trail) that each step was considered separately and fairly.

What Does ACAS Recommend in Disciplinary Procedures?

The ACAS Code of Practice is not law, but it’s the gold standard for UK employment processes. It says:

• If possible, different people should carry out the investigation and the disciplinary hearing.
• If that’s not possible due to size, you must still act fairly and explain why you combined the roles if challenged.
• Always follow a clear, step-by-step process (investigation → hearing → decision).

It’s worth reviewing your disciplinary and grievance procedures in your staff handbook or policies, and checking they align with ACAS principles. If you haven’t set these out yet, now’s the time-having the right documents both keeps you compliant and gives you a clear process to follow if things get tricky.

Can One Person Investigate and Chair the Disciplinary Hearing in a Small Business?

What if you run a tiny company, and the reality is you just don’t have extra managers to spare? ACAS recognises that sometimes there genuinely isn’t another suitable person. In this scenario:

• You can have the same person do both investigation and disciplinary, as long as you keep things as fair as possible.
• Document your reasons for combining the roles (e.g., staff numbers, no suitable alternative).
• Maintain a clear paper trail demonstrating that the investigation and disciplinary decision were carried out as separate thought processes.
• Offer the employee the right to be accompanied and to present their side of the story.

If your business grows, or if you can call on someone external (for example, an HR consultant or another trusted manager from a different branch), it’s wise to do so. You can also consult with employment law specialists if things feel especially complex (our detailed disciplinary guide explains more ).

Best-Practice Steps for Fair Disciplinary Procedures

To future-proof your process and lower your risks, here’s a step-by-step approach that reflects UK best practice (and is scalable as your business grows):

1. Have a Written Disciplinary Policy

This lets staff know what to expect and proves you take fair conduct seriously. At minimum, include:

• Examples of misconduct, gross misconduct, and unsatisfactory performance
• The step-by-step process you’ll follow (investigation, hearing, decision, appeal)
• Employee rights (such as accompaniment or opportunity to appeal)

Read more on drafting employee policies here.

2. Assign Different People, If You Can

If your team is big enough, aim for:

• Investigator - gathers evidence and interviews witnesses
• Disciplinary chair - decides, based on the facts, if action is warranted
• Appeals chair - reviews the case if the employee contests the outcome

In small firms, you may need to double up-but where possible, keep at least the appeal stage with someone who wasn’t involved earlier.

3. Keep The Process Objective and Transparent

• Don’t assume guilt from the outset; the investigation should be fact-finding, not fact-deciding.
• At the hearing, use the evidence but keep an open mind. Record your reasons for all key decisions.
• Make sure the case is judged on the facts, not hunches or personal feelings.

4. Offer Appeal Rights

Regardless of who did the initial stages, always let the employee appeal your decision to another individual if possible. If that’s not practical, consider using an external legal advisor to review the appeal stage (well-drafted contracts and policies help clarify these rights ).

How To Minimise The Risk Of Unfair Dismissal Claims

Ultimately, a tribunal will look at the whole of your process. If you follow best practice, keep paperwork, and act fairly, you’re well placed to defend your decisions. Here’s what else you can do to reduce risk:

• Be upfront: If your business is small, state your reasons for one-person process-and document it.
• Transparency: Keep records at every stage (meetings, outcomes, reasons for decisions).
• Seek outside help: It’s perfectly legitimate to consult an external investigator or HR expert if your business lacks capacity or you want added protection. This is common in sensitive or high-risk cases.
• Keep your legal documents up to date: Make sure employment contracts and staff handbooks reflect your process. Outdated documents could spell trouble down the line (here’s more on staff contracts in the UK ).

You can learn about the basics of ending employment contracts fairly here.

What If The Employee Alleges Bias?

If your disciplinary outcome is challenged on the basis that the same person handled both stages, you’ll need to show:

• You had reasonable grounds (e.g., staffing) for combining the roles.
• The investigation and hearing were distinctly recorded and reasoned-showing no predetermination.
• The employee had every opportunity to present their side and respond to evidence.

If the procedures are otherwise clear and robust, and you’ve followed the ACAS Code as closely as possible, a tribunal is less likely to find against you-especially for small businesses. Still, always document your rationale for process decisions.

Other Key Compliance Steps for Disciplinary Procedures

To further protect your business and staff, remember these essentials:

• Privacy and Data: Investigations can involve sensitive personal information-ensure you handle and retain this data in line with the UK GDPR and Data Protection Act 2018. Read up on business data protection here.
• Right to Accompaniment: Employees have the right to be accompanied at disciplinary or grievance meetings by a union representative or colleague. Make this option clear throughout your process.
• Natural Justice: Above all, aim to treat staff openly, fairly and consistently, so nobody feels “set up” or unfairly targeted. Document every step-for your own protection as well as theirs.

Key Takeaways

• It’s not unlawful for the same person to conduct a workplace investigation and chair a disciplinary hearing, but it’s best practice to keep the roles separate if possible.
• If you must combine the roles (especially in small businesses), document why, and make every effort to ensure both stages are carried out fairly and impartially.
• Follow the ACAS Code of Practice, and keep a clear record of your decisions, process, and reasons throughout.
• Always offer employees a chance to respond to allegations, and allow an appeal wherever practical.
• Review your disciplinary, grievance, and data protection policies regularly to ensure they are up to date and properly followed during issues.
• Consider seeking legal advice for complex or sensitive cases-proper procedures now help avoid more costly problems later.

If you need tailored legal advice or help with drafting and reviewing your disciplinary and investigation procedures, Sprintlaw’s team is here for you.
Call us on 08081347754 or email team@sprintlaw.co.uk for a free, no-obligations chat about your business needs.