A great deal of the available guidance on conducting workplace investigations relates to the form of your questions of the parties involved, and in particular to whether they should be open, closed, or leading.  This is the difference between:

• “And what happened next?” – open, because the answer can go off in any direction;

• “Did x happen next?” – closed, because it allows only a yes or no answer; and

• “And then x happened, didn’t it?” – leading, because it clearly points the witness towards a particular answer.

The big no-no in internal investigations is the leading question.  It risks suggesting that the investigator already has his/her conclusions made and is just looking for evidence to corroborate them.  In Court or Tribunal, excessive leading of the witness will be valid ground for objection and some discretion lies with the Judge to discount or attach less weight to evidence given in response to such a question.  But what significance does it have in an internal workplace investigation which is likely to be some steps back in time from the issue which forms the grounds of a later claim?  Will evidence of your asking leading questions in the course of your investigation invalidate the outcome or leave open to challenge any decisions then taken on the basis of what you found?

Not asking leading questions is harder than it sounds, especially where as investigator you do already have at least a provisional view of who did what and why.  Seeking affirmation of one’s understanding is just human nature.  The obvious problem is that seeking corroboration to support a provisional or developing version of events (which is quite legitimate) is outwardly indistinguishable from doing so to reinforce a conclusion already made (which is not).  Because even professional advocates get on the wrong side of this on a regular basis, sometimes even inadvertently, avoiding leading questions is not an absolute requirement of a legally-robust investigation.  That would be a counsel of perfection and that is simply not required, only that your conduct of the enquiry is reasonable.  A handful of such questions won’t make any material difference to this, especially if they relate to relatively uncontroversial matters or if the same evidence is given by others or repeated by that employee at a later point without that prompting.  You would also gain additional protection against a challenge to your findings if the witness gets a note of your meeting with them and does not seek to revisit what they said, or if you allow the employee to be accompanied by a colleague or trade union representative in the meeting and they don’t take the point.

However, there are still limits and the good investigator will try to keep inside them.  Where key facts remain unresolved, it is better to ask an open question about them than for the investigator to present his/her understanding of the position and then ask the witness to agree or disagree.  That can blur recollections and lead to witnesses losing track of what they know for a fact as against what they have been told is a fact.  Once the broad factual outline is established, a move to more closed questions can then help nail down individual details within it.  Leading questions are best kept for facts which are completely incontrovertible or to echo what the witness has said and so help him/her feel heard.  In a bullying investigation, for example, you might start with open questions – what sort of thing did he do which you say was bullying?  Then closed – and on that occasion, what were the words he used?  Then (technically) leading – and that is what made you feel threatened and demeaned, yes?  That is leading because it suggests the answer, but is not a problem because since that is the subject of the grievance, you already know how the employee will respond.

Do keep in mind that the Employment Tribunal will not expect the standards of a professional advocate and therefore that the likelihood of its ruling your investigation an unsafe foundation for the subsequent actions of the employer is usually negligible.  The principal exception to that will be where your questions are so consistently leading, especially towards one side of the argument at the expense of the other, that you forfeit any appearance of impartiality.  That will put a bus through the Acas guidance, will certainly take your investigation outside the range of reasonable responses, and so greatly risk undermining the legitimacy of that subsequent action.

Related to this is avoiding the temptation to use the language of cross-examination that you may have seen in court television dramas.  First, it’s just television. Second, you are not seeking to discredit the witness evidence, so any challenge from the investigator beginning “I put it to you …” is almost certainly a mistake (quite aside from what a colossal charlatan you feel saying it) , along with “Is that what you’re telling me?  Really?” and televisual rolling eyes, theatrical sighing or derisive snorting.  However it is your job to test what you are hearing, so there is nothing at all wrong with pointing out obvious consistencies within the witness’ evidence or between his and someone else’s, and asking him nicely to explain them.  You are not Holmes or Poirot, so not spotting tiny clues or cues for new lines of enquiry won’t do you any harm. You don’t have to go down every possible evidential rabbit hole to see what you can find, just in case. But not picking up clear gaps or clashes within the evidence – the sort of thing where if sat in an ET in a year’s time you would be quite unable to explain how you had missed it – is a different matter. It will indicate that you weren’t really focussing on what you were hearing or indeed on what you were doing there in the first place. Seeking clarification is part of your role but overt scepticism or attack is not.