Experts rightly pride themselves on their knowledge and understanding of their specialist area but its fair to say that judge’s are sometimes less than impressed when expert evidence takes on a life of its own.

They particularly dislike expert evidence on subjects that really don’t require any expertise.  Glenfiddich Wind v Doranell Windfarm  was a dispute about wind power generation where two experts were asked to interpret and describe the UK’s Balancing and Settlement Code (BSC) which governs how energy generators are paid.  The problem the judge saw was that “their descriptions were not matters upon which they possessed any special knowledge or experience, and had no greater value than had they been expressed by someone plucked  at random from the street to whom the BSC processes had been described.” They had in effect, although knowledgeable and balanced in their approach, become conscripts in an expert arms race which had  grossly and unnecessarily complicated the presentation and consideration of the merits of the case

Even when expertise is genuinely required it can sometimes expand beyond sensible boundaries. In Energygen & Hyundai v HD Korea Shipbuilding   there was a need to know the correct translation of the phrase “sah-up-booh-moon” but as the judge explained, “I mean no disrespect to either expert when I observe that I doubt that quite so much academic firepower was necessary to resolve this very narrow issue. “

But in a different twist on the theme,  factual witnesses can sometimes over-emphasise the need for expertise.  DRPS Property  v Residential Marine was a dispute over a small parcel of land on the Medway that may or may not have existed at a particular point in time.

One of the factual witnesses explained, which the judge accepted, that she was not an expert on maps or plans. However, as he put it  the refrain that she was ‘not an expert’ “was trotted out any time that there was anything difficult or contrary to her case in any of the maps and plans, no matter how obvious the point was on the face of the document and how little expertise was needed to grasp the point”

So as so often, the rule is that witnesses, whether expert or not, should stick to what they know but avoid hiding either in denials of the obvious or in thickets of irrelevant material, however well informed.