Once you have done all the scoping out and refining of allegations you can before starting your investigation, there will come the point where you have to raise the allegations made with the people they are made against.
If the allegations are false, those people will be very angry. If they are true, they will be angrier still. As a minimum they foresee hours they don’t have being hoovered into an investigation they don’t want into conduct they didn’t commit with who knows what acrid taint of smoke without fire clinging to their reputation thereafter. At worst, it is career-threatening stuff with their job, their home, their marriage, etc. all at stake.
People who are very angry do foolish things in response, whether it is an aggressive verbal attack on the complainant, to his face or behind his back, withdrawing from all unnecessary communications with him into a sullen and resentful silence or what is usually the very least sensible way of reacting, i.e. some form of counter-grievance. It is hard not to sympathise – one way or the other, an allegation to your employer that you have committed a criminal act or breached some legal obligation or have discriminated or sought to cover up wrong doing is personally and professionally pretty challenging. Not letting such an allegation affect your workplace behaviour towards that individual in any way can feel like the hardest thing in the world.
But challenging or not, and however hyperbolic or provocative the terms of the disclosure or grievance, retaliation will very likely be unlawful. It will be victimisation under section 27 Equality Act if the disclosure relates to alleged discrimination and detriment under section 47B Employment Rights Act if it amounts to whistleblowing. In both cases, retaliation may generate a claim not just against the employer but also the individual doing the retaliating. An allegation of conduct which does not fall within either the Equality Act or the ERA is probably legally unprotected in that respect, but any decent grievance procedure will make it clear that good faith grievances are protected even if objectively unfounded, so any such behaviour by the colleague or manager potentially incriminated is going to be serious misconduct anyway.
Under both the Equality Act and the ERA the employer may escape vicarious liability for the retaliation of one employee against another if it can show that it took all reasonable steps in advance to prevent it (the “statutory defence”). Therefore before you get into the details of your questioning any person involved in the circumstances at issue, it makes good sense to issue them with a clear oral and written shot across the bows to the effect that whatever their contrary factual opinions and immediate emotional reaction to the disclosure or complaint made, they must not subject the maker of it to any less favourable treatment on that basis. Much more easily said than done, granted, but saying it is still half the battle.
This may also be a good point for discussion with them about any impending processes or decisions in relation to that individual – performance management measures, grievance meetings, redundancy selection exercises, bonus rounds, evaluations etc. – so that steps can be taken to head off or mitigate the risk that they will be alleged to use that process or decision to effect their retaliation for the complaint or disclosure. Should they step out of that process or at least add some visible objectivity by sharing it with someone not caught up in the employee’s allegations, for example? [NB this is not a legal requirement and may not be possible at all in small companies where there just isn’t headroom enough in the senior hierarchy to disqualify members of it from key management duties of that sort on the basis of what is at that stage possibly a mere assertion – the key is being seen to think about it. The obligation to take preventative steps also depends on the nature of the allegation and the degree of personal animosity or resentment it is likely to engender in the person accused – a technical breach of a legal obligation reported in a cooperative and remedial spirit is a very different thing from an allegation of willful and malicious conduct or harassment seemingly phrased to cause as much embarrassment as possible]
Where the identity of the maker of the grievance or disclosure is being withheld from the witness, the same applies – we recommend a clear instruction at the very outset of the investigation process to the effect that they should not take steps to find out who has made the allegation and that even if they do think they know who it is, retaliation is still a no-no. [NB: This is only the investigation stage, after all – if it turns into something disciplinary with prospective adverse impacts upon the witness, then they are very likely to have a right to know the identity of their accuser at that stage before any final decisions are taken].
That written instruction will be disclosable in litigation, especially if the employer seeks to escape liability for the retaliation via the statutory defence. Therefore do try to avoid anything in it which implies bias or pre-determination of the investigation or an assumption that the person concerned is innocent of what has been said – “I know this is all frightfully irritating and unnecessary but we really must be seen to humour X in his latest tedious little grievance-thingy, so would you mind awfully just leaving him be until it all blows over? Many thanks – see you at the bar later”, etc.