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HR guide to a formal grievance procedure

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Posted by Joanne Duck on 07 July 2020

If an employee has a concern or complaint concerning something or someone in the workplace, they may raise a formal grievance to their employer in an attempt to resolve this. 

Many grievances can be resolved informally. However, if this is not possible, an employee may consider raising a formal grievance. 


All employees have a right to raise a grievance at any point during their employment; there is no minimum level of service required with the employer.

There is no clear obligation on employers to investigate grievances raised by workers or employees who have already left their employment. However, to avoid possible costly and time-consuming employment tribunal claims and to help defend the employer in any potential employment tribunal claims, some employers also choose to investigate these grievances.  


ACAS Code of Practice

Before commencing any grievance procedure, the employer should familiarise itself with the guidance included in the ACAS Code of Practice on Grievances (“the Code”). This code provides practical guidance to the employer on how to correctly and fairly deal with a grievance. 

Compliance with the code is not mandatory. 

However, it is advisable that employers do comply with the code and can demonstrate this compliance because if a matter progresses to an employment tribunal, the tribunal will take into consideration whether both the employer and the employee complied with the code. If an employee wins their case, and the employer has failed to comply with the code, the damages awarded to the employee can be increased by up to 25%. 

Grievance procedure 

As well as the code, the employer should review its internal grievance procedure (if one exists). It is important to comply with any internal processes to avoid an employee becoming further aggrieved (i.e. because the employer is not complying with its own rules). 

Raising a grievance

An employee should raise a formal grievance in writing (“letter of grievance”) and without unreasonable delay after the incident to which the grievance relates. The employee will need to raise their grievance in line with the requirements of the grievance Procedure, i.e. employees should put their concerns in writing to their Line Manager, or if the complaint is about their Line Manager, to a member of the HR department. The written grievance should describe the nature of the complaint (including any relevant facts, dates and names or individuals) and the employee’s desired outcome, as well as including copies of any relevant documents or supporting evidence. 

The letter of grievance should provide as much factual evidence as possible to set out the nature of the issue to ensure it can be investigated as fully, accurately and promptly as possible. 

Investigation process

Once an employer has received a grievance, it should acknowledge receipt to the employee as soon as possible.


At the outset, the employer will need to determine who will investigate the grievance. The investigation process will involve gathering all relevant information on the issues the employee has raised in their grievance. 

An appropriate investigator must be appointed. Whether an investigator is deemed appropriate will differ on the specific facts of the grievance. 

Fundamentally, the investigator must be impartial. Therefore, anyone named in the grievance should not be the investigator. It is also advised that anyone close to the employee, e.g. their Line Manager, is avoided if at all possible as this may cause unnecessary tension between the individuals in their future working relationship. 

The investigator should also be someone of sufficient authority to be able to deal with the matter. Usually, grievances can be investigated by a member of the human resources department. However, for grievances which have a high level of complexity and seriousness, it may be more appropriate to have a senior manager investigate. 

NOTE: When deciding as to who should investigate the grievance, an employer must give thought to who will deal with any appeal should the matter progress to this. The employer must ensure that there is a suitable individual available, with sufficient authority and impartiality, to conduct any appeal hearing. 

Action plan

The investigator needs to ensure that they undertake a thorough and detailed investigation so they can reach an informed outcome at the end of the grievance procedure.

At the outset, this may involve:

  • Review of the letter of grievance;
  • Checking relevant policies and procedures;
  • Identifying potential sources of evidence;
  • Identifying possible parties relevant to the investigation;
  • Deciding how and when to collect the evidence; and 
  • Deciding when and where the grievance hearing should take place.

Ideally, the investigator will come up with a plan as to how they will conduct the grievance before the investigation.

Grievance hearing 

The investigator will need to invite the employee to attend a grievance hearing in writing. The grievance hearing is an appropriate forum to discuss their grievance and to obtain a full understanding of what their concerns are and where further investigation is required. In the written invitation to the hearing, the investigator should explain that they will conduct the meeting and confirm that another individual, usually a member of the human resources department, will be in attendance to take notes.

It is advised that all employees are provided with the right of accompaniment at the hearing. This should be stated in the invitation letter, noting that the employee is entitled to bring an authorised Trade Union representative or a fellow colleague with them.

The grievance hearing should be held without unreasonable delay. The ACAS guidance states that the grievance hearing should, ideally, be held within five days. This is not always possible. However, if there is a longer period before the hearing, the employer may need to show the reasons for this delay if the matter progresses to an employment tribunal. 

At the outset of the hearing, if the employee has brought a companion, it is advisable to establish the identity and role of this individual. The companion can either be attending as a witness, in which case they will just take notes for the employee, or they can attend as a representative. If the companion is acting as a representative, they can help the employee put forward their case. However, in neither role does the companion have the ability to answer questions directly addressed to the employee. 

Furthermore, the employee should be made aware before, or at the beginning of the hearing that they are forbidden from audio recording the hearing. It can be explained to the employee that the note taker is present to ensure that an accurate reflection of the hearing is obtained. The investigator should confirm that the employee will be sent the notes of the meeting shortly after the hearing so that they have the opportunity to review and approve their contents. The employer should get the employee to sign and date the notes to indicate their agreement as this will help protect the employer’s position in any potential Employment Tribunal claims. 

Where witness evidence is needed as part of the investigation, this should be collected separately to the Grievance Hearing. The employee has no right to view any witness evidence collected as part of a Grievance or cross-examine the witnesses. While the employer can technically allow witnesses to attend a Grievance Hearing, it is strongly advised that, for ease, this does not occur and all other evidence is obtained separately.


The period following the Grievance Hearing is where the investigator will undertake the majority of their investigation. This may involve:

  • Speaking to witnesses and obtaining witness evidence; 
  • Gathering evidence, e.g. CCTV footage; and 
  • Further meetings with the employee if necessary. 

It is advised that the investigator completes an investigation report which documents their investigation and how they arrived at the ultimate grievance outcome. 


Once the investigator has completed a full investigation, they must, without unreasonable delay, inform the employee of the outcome of the grievance and of the action, if any, that has been decided to resolve the grievance.

The employee must be informed of the outcome of their grievance in writing. This letter should demonstrate how the final decision was reached. It will also need to provide the employee with the right to appeal the decision.

Investigators can meet with the employee face-to-face to confirm the outcome of the grievance, before sending the Outcome Letter if desired. However, this is not necessary.   


If the employee decides to appeal the decision, the employer will need to select an impartial individual who will be able to manage this. 

The employee must raise their appeal in writing. This must be without unreasonable delay. It is advised that the employer sets a time limit for the employee to raise an appeal. If an employee raises an appeal outside of this timeline, it is up to the discretion of the employer as to whether it wishes to investigate this further. In some circumstances, the employer may feel it is beneficial to investigate a late appeal to avoid further repercussions via a possible Employment Tribunal claim.

The employee’s appeal letter should state, in detail, the grounds upon which they are appealing the employer’s decision. 

The appeal can either be heard as a review or a re-hearing. A review is where the Appeal investigator will simply go through the original Grievance investigator’s report and check that the grievance has been properly and thoroughly investigated and that based on the review of the evidence available, the decision made was a reasonable one. A re-hearing is where the Appeal investigator will conduct their investigation into the grievance – i.e. a new investigation will occur. A re-hearing is only necessary if the employer believes there has been a fundamental procedural flaw in the original Grievance investigation. The normal course of action will be a review. 

Once the appeal hearing has been held, the appeal investigator will need to communicate the final decision to the employee, without unreasonable delay.

Once again, the outcome must be confirmed in writing. The appeal investigator may wish to speak to the employee in person before sending this letter, but this is not necessary. 

Overlap with disciplinary 

Where an employee is the subject of a disciplinary procedure and raises a grievance, the employer must decide on the most appropriate cause of action for dealing with this.

Usually, it is customary to pause the Disciplinary Procedure until the employee’s grievance has been fully dealt with. However, if the employer believes that it can deal with the Grievance and Disciplinary concurrently (i.e. alongside each other), ACAS guidance has stated this will be acceptable in certain circumstances. 

It is normally best to seek legal advice from an employment lawyer if a grievance is raised during a disciplinary procedure. 

About the author

Joanne Duck


Joanne advises employers of all sizes on a range of employment law matters. She has experience across a variety of industries and sectors from manufacturing to education.

Joanne Duck

Joanne advises employers of all sizes on a range of employment law matters. She has experience across a variety of industries and sectors from manufacturing to education.

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