2. When the employee wants a witness present: who takes the statement; who asks them to attend; should they be compelled; who can ask questions of the witness; witness anonymity; which evidence is to be preferred.
ACAS Code: “The employee should also be given a reasonable opportunity to ask questions, present evidence and call relevant witnesses. They should also be given an opportunity to raise points about any information provided by witnesses. Where an employer or employee intends to call relevant witnesses they should give advance notice that they intend to do this.”
The grievance investigator should take a statement and ask witness/es to attend (if necessary).
Employees who are witnesses could – further to obligations owed to the employer – be compelled to attend if absolutely critical to the disciplinary process. However, the employer should consider whether other evidence will suffice and if there are other options which should be pursued as an alternative (such as the witness giving evidence anonymously (see further below) or the witness being persuaded to attend). In certain cases, forcing an employee to provide witness evidence against their will would amount to constructive dismissal (following a fundamental breach of the implied term of trust and confidence); as ever this is very much fact-sensitive.
The need for the privacy of all individuals concerned (the accused employee and the witnesses) must be emphasised by the investigator and HR. The investigation must be confidential so each witness should not discuss it with anyone else
The witness statements should be signed.
Reluctant witnesses and those who wish to remain anonymous are a common problem. The investigator should explore why the individual wants to remain anonymous. When considering the reasonableness of an employer’s actions and decisions, a Tribunal will consider the investigation and whether (i) the employee knew the case against them; (ii) the employee was given sufficient detail to be able to respond fully and put forward a defence; and (iii) it was necessary for the witness to be anonymous.
In some circumstances the witness’ motives may need to be questioned and corroborating evidence (for the accused and the witness/es) should be sought.
The investigator should question whether the witness has any reason to lie? Does the witness have a bad/good reputation within the company? Does any individual appear to have fabricated evidence (e.g. to exonerate self)? Has the witness had a previous disagreement with the accused employee?
If it is possible to anonymise the witness evidence without causing unfairness to the accused employee, then the witness interview should be conducted as standard and the statement later anonymised (i.e. any information pointing to their identity should be removed subsequently) (Linfood Cash & Carry Limited v Thompson  IRLR 235). Clearly that will be very difficult or impossible in a small company or department.
Corroboration of witness evidence is always desirable. After witness statements have been taken, further investigation may be required to verify or undermine the information given.
At the hearing, the accused employee should be given a reasonable opportunity (potentially with their companion’s assistance) to present their version of events and produce any evidence in support, including calling any relevant witnesses if they have given advance notice of their intention to do so. In addition, they should be allowed to “raise points about” information given by a witness.
If a witness is liable to be intimidated by the accused employee, the investigator can ask the latter to leave for part of the hearing. The companion (or representative) could be allowed to stay.
Non-binding ACAS guidance states that it is good practice to allow the accused employee’s companion to participate as fully as possible in the disciplinary hearing, including by asking questions of witnesses.
As always, if there is a conflict of evidence: One person could be believed over the other. Or the investigator could conclude that it is not clear what happened; and, in that scenario, the accused employee would be given the benefit of the doubt.