Your rights in a disciplinary investigation


What is a disciplinary investigation?     

An investigation is a fact-finding mission. No more and no less. The purpose is to find out on the balance of probabilities whether there is a case to answer. It is not an exercise to find out whether an employee is guilty or not. Workplace investigations can be carried out in a variety of situations, and not just in disciplinary action. Investigations happen for example where there are;

  • Matters of misconduct
  • Capability
  • Bullying and harassment
  • Absence
  • Grievances
  • Whistle blowing allegations

You continue to have employment rights during the investigation.  The ACAS Code of Practice on Disciplinary and Grievance Procedures applies to any matters relating to discipline. Your employer has a legal duty to act reasonably and use a fair procedure. The ACAS Guide gives directions on what it is to act reasonably and fairly, and the duties are further developed by the Courts and Tribunals in case law.

  • The duty to act reasonably and use a fair procedure applies to the Investigation and anything that falls within this activity.
  • Your employer can only conduct a disciplinary investigation for one of the 4 reasons in S98 ERA (1996). Redundancy is not included in discipline.
  • If your employer does not act BOTH reasonably and use a fair procedure during investigation, a subsequent dismissal will be unfair and you would have a successful claim in the Employment Tribunal.
  • Employee Rescue resources provide you with audits, sample letters and instructions to check whether the Investigation was done reasonably and in accordance with a fair procedure.
  • If it wasn’t you should raise a grievance with your employer. 


Resources Available

Surviving a Disciplinary Investigation at work

Disciplinary action and capability

Discrimination at work

Surviving a workplace suspension

How to fight dismissal on Probation

How to survive a criminal charge, conviction or caution at work

Social Media and Unfair Dismissal

Surviving Capability and Performance Management

The Disciplinary Hearing

Alcohol and Drugs at work

How to prepare a schedule of loss for unfair dismissal


The relevant law


The Duty to Act Reasonably

The duty to act reasonably is also known as the band of reasonable responses. It is a legal duty laid out in Section 98 (4) (a) and (b) Employment Rights Act 1996. S.98 (4) (b) says that the duty to be reasonable should be decided in accordance with equity and the substantial merits of the case. Equity here means natural justice, procedural fairness, an employee’s personal circumstances, common sense and common fairness. Substantial merits here means “whether an employee’s behaviour or performance warranted dismissal”.


The Burchell Test

The duty to act reasonably was explained in the case of British Home Stores v Burchell (1978). Where there is a dismissal, the court said that an employer must prove that at the time of the dismissal

  1. they believed that the employee was guilty of misconduct
  2. the belief was based on reasonable grounds
  3. at the time of the belief they had carried out a reasonable investigation

The Balance of Probabilities

This means that it is up to your employer to prove that you have a case to answer. This task of proving or disproving is commonly described as “the burden of proof”. The Burden of proof is decided on “the balance of probabilities” The balance of probabilities means that something is more likely than not to have occurred, or it is more likely than not that the incident did not occur. If the probabilities are equally balanced then your employer has not satisfied the burden of proof.

The Employment Tribunal will not consider whether you were actually guilty of the misconduct, but whether your employer believed and had reasonable grounds for believing that you were guilty of the misconduct at the time the decision was made. The only way that your employer can prove that they believed and had reasonable grounds for this belief is by proving that they acted within S98(4) ERA 1996.


The Duty to follow a Fair Procedure

A fair procedure is determined by reference to rules of natural justice and the following;

  • Whether the reason for dismissal falls within one of the fair reasons in Section 98(2) Employment Rights Act 1996 – Capability or Lack of qualification, Conduct, Redundancy, statutory restriction, some other substantial reason (SOSR). See Dismissal.
  • ACAS Code of Practice
  • Your employer’s Disciplinary Policy and Procedure
  • The implied duty of mutual trust and confidence


The Polkey Principle or Rule

The famous case of Polkey v. A. E. Dayton Services Ltd [1988] is sometimes called the “no difference” rule. In this case the House of Lords said that an employer’s failure to follow a proper procedure (including investigation) is almost guaranteed to make any dismissal unfair. The Employment Tribunal may reduce the level of compensation if a fair procedure would still have led to a dismissal (The Polkey Reduction).

This means that even if the employer was reasonable under S98 (4) ERA 1996, but breached the duty to follow a fair procedure, then the dismissal will be unfair.

The Polkey Reduction

If your employer was reasonable under S98 (4) ERA 1996 but did not use a fair procedure, the Employment Tribunal will reduce your compensation because you would have been dismissed if fair procedures had been followed.

In every investigation the Band of Reasonable Responses (Burchell Test) AND a Fair Procedure must be applied. If they are BOTH not present, a dismissal will be unfair.

An employer who has failed to conduct a proper investigation into an employee’s misconduct was not able to successfully argue in subsequent unfair dismissal proceedings that the outcome (dismissal) would have been the same even if the investigation had been properly conducted. In A v B [2003]The Employment Appeal Tribunal said that the employer’s investigation into an employee’s alleged misconduct was not reasonable in all the circumstances and, accordingly, his dismissal was unfair. It was no answer to the defects in the investigation to say that even if it had been reasonable, the decision to dismiss would still have been taken.


Rules of Natural Justice

Natural justice is legal language for two ancient rules from the Romans who believed that some legal principles were self-evident and did not require a statutory basis. It has been replaced and extended by the general “duty to act fairly”. There are two pillars of natural justice. The rule against bias is known as “nemo iudex in causa sua”. It means that no person can judge a case in which they have an interest.  “Audi alteram partem” means “hear the other side too”. It is most often used to refer to the principle that no person should be judged without a fair hearing in which each party is given the opportunity to respond to the evidence against them.  The principles of natural justice represent the basic requirements of fair procedure.  The minimum requirements are:

  • Notice to the Employee of the specific allegation of misconduct to which he or she must answer and of the likely consequences if the allegation is established.
  • An opportunity which must be real as opposed to a nominal one, for the Employee to attempt to refute the allegation or to explain or mitigate his or her conduct.
  • An unbiased consideration of the Employee’s explanation in the sense that consideration must be free from pre-determination and uninfluenced by irrelevant considerations.

The ACAS Code describes the 3 main elements of the principles of natural justice in a disciplinary situation.

Hearings – audi alteram partem

  • You must know the detail of the allegations against you and the evidence in support of those allegations.
  • You must be allowed an opportunity to present your case where your employment rights may be adversely affected by a decision-maker.
  • The decision maker must you an opportunity to prepare your case and defend yourself with evidence and arguments.

Bias – nemo iudex in causa sua

  • The decision maker must be unbiased during the hearing and when making the decision.
  • Investigators and decision makers must act without bias in all procedures connected with the making of a decision.
  • The decision maker must be impartial and must make a decision based on a balanced and considered assessment of the information and evidence without preference for one person over the other.
  • Investigators and decision makers should avoid conflicts of interest and anything that would appear to be bias.


  • Any decision must be based upon logical proof or evidence.
  • Investigators and decision makers should not base their decisions on gossip, speculation or suspicion.
  • Investigators and decision makers should be able to show the evidence on which their recommendation or decision is based.
  • All the evidence must be provided to the accused person.


Best of the web

ACAS – Conducting workplace investigations



This resource is published by Employee Rescue Limited. Please note that the information and any commentary on the law contained herein is provided for information purposes only. The information and commentary does not, and is not intended to, amount to legal advice. Employee Rescue accepts no responsibility for any loss occasioned to any person acting or refraining from action as a result of the material contained in this publication.

Further specialist advice should be taken before relying on the contents of this publication. You can send an e-mail to for such specialist advice if required.

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