Last reviewed 13 December 2017

Stuart Chamberlain, Croner-i author and employment law consultant, looks at disciplinary investigations, whether past misconduct should be taken into account in deciding the appropriate penalty, and concludes with some practical advice to employers.

It is well established that an employer must conduct a reasonable investigation into alleged misconduct and that any subsequent decision on the matter must be that of a reasonable employer (the “range of reasonable responses” test). Otherwise, any decision to dismiss the employee may be unfair.

The Employment Appeal Tribunal (EAT) addressed a novel related issue in NHS 24 v Pillar [2017] UKEATS/0005/16: whether a disciplinary investigation can contain too much detail. Ms Pillar, a triage nurse, had been dismissed for gross misconduct: she had sent a patient who had experienced a heart attack to an out-of-hours GP rather than calling 999. She successfully claimed at the employment tribunal that the dismissal was unfair because the investigatory report, on which the employer had principally based the decision to dismiss, included details of two previous acts of misconduct for which no disciplinary action had been taken — she had been given a development plan and training.

When an investigation may be necessary

Where a potential disciplinary matter has arisen, the employer should conduct an investigation into the background and surrounding circumstances to gather all the relevant facts.

Common situations that will often require an investigation include:

  • receiving a grievance from an employee

  • allegations of bullying and harassment

  • potential disciplinary matters against an employee.

Why the investigation is important

A reasonable investigation by the employer is a key component of a fair dismissal procedure. This requirement is enshrined in the Acas Code of Practice on Disciplinary and Grievance Procedures. Paragraph 4 of this Code stresses that employers should carry out any necessary investigations, to establish the facts of the case. Thus, in potential disciplinary investigations, a flawed or incomplete investigation can undermine the disciplinary process and leave employers vulnerable to claims for unfair dismissal.

If an employer does go on to dismiss the employee, it must be able to show before an employment tribunal that it:

  • genuinely believed that misconduct had occurred

  • had reasonable grounds for this belief

  • had arrived at this belief after a reasonable investigation.

Therefore, for a dismissal to be fair, an employer must be able to show that it came to its decision to dismiss as a result of a fair and thorough investigation. Disciplinary procedures involve a two-stage process: an investigation to gather all the relevant material to enable the employer to reach a decision based on all these factors. The courts and tribunals have been directed to apply “the range of reasonable responses” test to evaluate whether the employer has conducted sufficient investigation in all the circumstances of the case.

Investigation is just as important when an employee raises a grievance: if the grievance is not upheld, the evidence collected during the investigation can be used to explain the reasons behind this and show an employee that their grievance was taken seriously.

Tips for employers

In order to ensure that a disciplinary investigation meets its legal requirements, and thus minimise a liability for unfair dismissal, an employer instigating a disciplinary procedure for an employee accused of misconduct should take into account the following practical points.

A fact-finding exercise

Always remember that an investigation is a fact-finding exercise to collect all the relevant information on a matter. It is not a disciplinary hearing.

Follow the Acas code

Always follow the recommendations of the Acas Code of Practice on Disciplinary and Grievance Procedures. An employer’s failure to follow the Code could lead, in the event of the employee being successful in a claim for unfair dismissal at the tribunal, in an uplift of up to 25% in the compensation awarded to that employee.

Ensure that the investigating officer is appropriate

The person who is charged with investigating the allegations is usually the employee's line manager. If, however, this line manager is already involved in the matter (that is, the line manager has actually made the complaint against the employee or is otherwise a witness in the investigation), the employer should appoint an alternative manager to conduct the investigation process. It is important that wherever possible, the investigating officer is different to the manager who will chair any disciplinary hearing that could decide to dismiss in order to avoid allegations that the hearing outcome has been pre-judged.

The investigator should be given clear guidance on what exactly they are required to investigate, and how their findings should be reported. An investigator should try to be fair and objective when carrying out an investigation, looking for evidence that supports or disproves the allegations. The investigation should aim to establish the facts of the matter by collecting relevant evidence — such as witness statements, written documents and physical evidence — and drawing a conclusion.

Ensure that the employee understands the allegations against them

In some circumstances, it may be necessary for the employer to hold an investigatory interview with the employee accused of misconduct.

Consider whether suspension is necessary

As has been pointed out by the case law, employers should not adopt a “knee-jerk reaction” and immediately suspend an employee who is facing charges of misconduct. Suspension is not a neutral act — it is a serious step that inevitably casts a shadow over the employee’s competence and reputation. Inappropriate suspension could lead to the employee resigning and claiming constructive unfair dismissal on the ground that the employer had breached the implied term of trust and confidence. The employer could also face a claim for damages for any resulting psychiatric injury suffered by the employee.

If the employer does decide to suspend the employee where the allegation is one of serious misconduct (for example, in order to preserve the integrity of the investigation process or to safeguard the business and/or its employees), then it should be on full pay. The Acas Code of Practice also recommends that any period of suspension is kept under review and if during the investigation process it becomes clear that suspension is no longer needed, the employee should be allowed to return to work.

The investigation should be carried out without unreasonable delay

Even where the guilt of the employee seems obvious, it is still important that an investigation is carried out. The employee may have a plausible explanation for what they were doing which could mean that a disciplinary hearing is not required, and this will not be discovered unless an investigation is undertaken. It is also important that any investigation is undertaken without unreasonable delay.

The employee should be allowed a companion

There is no statutory right for an employee to be accompanied at an investigation meeting, but allowing a companion to attend could be some insurance against any subsequent argument over the nature of the evidence and the fairness of the dismissal. Always check the organisation’s disciplinary policy.

If the employee facing the allegations is disabled, the employer has a duty of reasonable adjustment: it may well be reasonable for an employer to allow a disabled employee to be accompanied or to change the location or arrangements for an investigation meeting to alleviate any disadvantage.

The investigating officer should always recommend next steps

At the end of the investigation, the investigating officer should review the evidence collated and make a recommendation based on what has come out of the investigation process.

Can past misconduct be taken into account?

Although the employment tribunal in Pillar held that the employer’s decision to dismiss Ms Pillar on grounds of misconduct was within the band of reasonable responses, it agreed with her that the dismissal had been procedurally unfair as the investigatory report had included details of earlier misconduct.

In Diosynth v Thomson [2006] IRLR 284, the Inner House of the Court of Session in Scotland stated that “spent” (that is, expired) warnings should not be taken into account in future disciplinary proceedings. However, two years later, the Court of Appeal took an alternative and wider view in Airbus v Webb [2008] IRLR 309: where the employee’s misconduct constituted a dismissible offence, the employer could rely on previous conduct when determining the appropriate disciplinary penalty.

This was followed earlier this year by the EAT in Stratford v Auto Trail VR Ltd [2017] UKEAT/0116/16 when the employee was dismissed for misconduct that normally would have resulted in a final written warning. Mr Stratford’s disciplinary record, however, was extremely poor — there had been 18 separate incidents, including final written warnings, during his 13 years’ service with the company. The employer had lost confidence that Mr Stratford would ever improve and took the history of the expired warnings into account when deciding to dismiss him.


In Pillar (see above), the EAT overturned the employment tribunal’s finding that the nurse’s dismissal was unfair because the investigation — and therefore the decision to dismiss — relied on previous issues. There are a number of points from this case that are of importance to employers.

  • The EAT reiterated in its judgment that the disciplinary procedures should involve a two-stage process: the investigating officer is required to gather all available evidence in order that the disciplinary officer can make a decision based on all the relevant facts.

  • It is highly unlikely that including too much information in the report will render a dismissal unfair — unless the investigating officer is overzealous.

  • The case is another example of the extent to which previous conduct (but tread carefully with expired warnings) can be taken into account in making a disciplinary decision.

  • The test for a “reasonable” investigation is whether it is “sufficient”.

  • The employer remains subject to “the range of reasonable responses” when a tribunal is deciding whether dismissal was fair.

And, finally, a reminder that every case will turn on its own facts.