Expert Witness and the Courts: Lessons from Recent Cases
There are lessons for expert witnesses in a number of recent court decisions.
1. Failing to comply with directions
In Mayr and Others v CMS Cameron McKenna Nabarro Olswang LLP  EWHC 3669 (Comm) an expert was debarred from giving evidence for the claimants after failing to engage in a discussion with the defendant’s expert, despite a direction to do so. The claimants argued that as the expert was independent, he was not under their control. However the judge found that, even if his failure to comply was not due to the claimant’s instruction, they were at very least aware of what he had done and should have made clear that this was unacceptable.
The lesson for experts is: do not disregard court directions.
The lesson for solicitors is: make sure your expert understands the importance of complying with directions.
2. A late change of mind
In Bakrania and Another v Shah and Others  EWHC 949 (Ch) the claimants’ case turned on valuation evidence. Their case collapsed when their valuer changed his mind and agreed with the opposing valuer’s valuation of some land.
The lesson for experts is: don’t put yourself in a position where you have to change your mind – put in the work to make sure you get the answer right first time.
3. Not reporting on time
In X and Y (Delay: Professional Conduct of Expert)  EWFC B9 HH a paediatrician jointly instructed in family proceedings failed to report 6 months after she was instructed. She also failed to attend court to explain the delay. There is a particular importance in experts reporting promptly in family proceedings where the welfare of children or vulnerable adults is concerned. The judge described her conduct as unacceptable and criticised her in the following terms:
‘I am deeply concerned about the way Dr Ward has behaved in this case. It does not meet the standards expected of an expert witness or the expectations of the court in this particular case. It cannot be allowed to pass without comment. That comment should be placed in the public domain.’
The lesson for experts is: meet your deadlines, particularly where vulnerable people depend on you doing so or risk devastating public criticism.
4. Usurping the judge’s function
In Prosser v British Airways plc  EW Misc B13 an expert gave his opinion as to the reliability of the account given by one of the parties. The judge disregarded those comments. Determining facts and assessing witness evidence is a matter for the judge and not an expert.
In the face of competing accounts, give alternative opinions based on the alternative accounts.
The one qualification to this is that sometimes an account may be inconsistent with a matter within an expert’s expertise. For instance if a witness’ account of events is inconsistent with the science, and that science is within the expert’s expertise, the expert can comment.
The lesson for experts is: you are not the judge – it is not for you to determine facts and you will annoy the judge if you try to do so.