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Disciplinary Investigations – Can an investigation be too thorough?

A dismissal for misconduct will be unfair under section 98 of the Employment Rights Act 1996 unless at the time of dismissal:

  • The employer believed the employee to be guilty of misconduct

  • The employer had reasonable grounds for believing that the employee was guilty of that misconduct and

  • At the time it held that belief, it had carried out as much investigation as was reasonable.

The tribunal must then consider whether the employer’s decision to dismiss an employee falls within the range of reasonable responses that a reasonable employer may have adopted in those circumstances.  The “range of reasonable responses” test applies to both the decision to dismiss and the adequacy of the investigation.

Expired disciplinary warnings should not be a determining factor in a decision to dismiss (Thomson v Disosynth Ltd [2006] CSIH 5). However in Airbus (UK) Ltd v Webb [2008] IRLR 309 the Court of Appeal held that a “flexible” approach was required and Diosynth did not mean that a tribunal could never take account of previous conduct that had been the subject of expired warnings.

Mrs Pillar was a triage nurse employed by NHS 24 (Scotland’s telehealth organisation) to take telephone calls from members of the public. Her role was to evaluate a caller’s described symptoms and to decide the most appropriate medical help.  In December 2013, Mrs Pillar made a clinical error when she directed a caller who was having a heart attack to an out of hours GP service instead of making a 999 emergency call for an ambulance.  The NHS 24 treated this as a Patient Safety Incident (PSI) and it led to disciplinary action and Mrs Pillar’s subsequent dismissal for gross misconduct.

Mrs Pillar had been involved in previous PSIs in August 2010 and July 2012. The first PSI also involved a failure to identify that a patient was having a heart attack.

Both these previous incidents were dealt with by way of providing a development plan and additional training rather than disciplinary action.  Details of these incidents were included in the investigatory report for the purpose of the disciplinary hearing that led to Mrs Pillar’s dismissal.

Mrs Pillar brought an unfair dismissal claim in the employment tribunal and argued that it was unfair for the investigating officer to have included the earlier PSIs when they had themselves not led to disciplinary action.

The employment tribunal held that the employer was entitled to treat the latest PSI as gross misconduct in view of the risk to patients, and that a dismissal was justified.  However the dismissal was procedurally unfair because it had not conducted a “reasonable investigation” as it was unreasonable for the employer to consider the previous incidents when making its decision.

The employment tribunal considered that Mrs Pillar’s actions had contributed to her dismissal and reduced her compensation by 70%. NHS 24 appealed the decision to the EAT.

The EAT allowed the appeal.  It found that whilst there may be cases where an overzealous or otherwise unfair investigation process could fall foul of the Burchell test, the starting point for the test was the “sufficiency” of the investigation and not the gathering of too much information.  The EAT was unaware of any case in which it had been argued that an investigation failed the Burchell test because it included too much information.

Mrs Pillar argued that if, as in Diosynth, an expired warning cannot be a determining factor in a decision to dismiss, then surely conduct not treated as a disciplinary matter at all could never be such a factor.  The EAT held that the expiry of a formal warning gave the employee an expectation that it would no longer be a determining factor in future disciplinary action.  However in this case no expectation had been created as to whether the earlier PSIs would or would not be relevant to a future disciplinary investigation.

The EAT held that because the employment tribunal had found that the decision to dismiss was within the band of reasonable responses it was perverse that they should conclude that the dismissal was procedurally unfair. The employment tribunal had concluded the dismissal was procedurally unfair because of the failure to tell Mrs Pillar at an earlier stage of the likely consequences of further PSIs beyond those set out in her development plan. The EAT considered the employment tribunal had not explored the context or gravity of this procedural defect.

What does this mean for you or your business?

  • An investigation report will not normally be considered to have failed the Burchell test of reasonableness on the basis that it contains too much information.

  • Investigation reports cannot include details of everything and anything; the information must be relevant to the pertinent issues.

  • It is still the case that care should be taken when referring in disciplinary proceedings to past misconduct which was the subject of an expired warning. 

  • Where an employee has no expectation of a warning or other sanction not being used in future, it may be permissible to use that warning or other sanction in later disciplinary proceedings. 

  • It is for the investigator to put together all relevant information and for the decision maker to decide what to do with it.

  • If a disciplinary decision maker receives an investigation report that contains material that they consider is historic, unnecessary or inappropriate the decision maker should make clear in the decision that that information did not form any part of the decision.

What do you need to be doing now?

Consider if you have any live disciplinary hearings which make reference to past misconduct which is not the subject of a live warning and therefore if this is appropriate.


These notes have been prepared for the purpose of articles only. They should not be regarded as a substitute for taking legal advice.

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