The Supreme Court has stripped expert witnesses of their immunity from prosecution. But could the fear of being sued make them less likely to admit their mistakes?

On 14 March 2001, a motorcyclist stopped at a road junction in Liverpool and waited to turn. A car drove into him. The driver of the car was drunk, uninsured and was driving while disqualified. Apart from physical injuries, the motorcyclist suffered post-traumatic stress disorder, with resultant chronic pain.

He instructed solicitors soon after the accident and they in turn appointed a clinical psychologist who prepared a report broadly supporting the claim, which was made against the Motor Insurance Bureau.

The defendant, of course, appointed another clinical psychologist, who concluded that the motorcyclist was exaggerating the symptoms. The judge ordered the two experts to prepare a joint statement.

The joint report was not what the motorcyclist’s solicitors were expecting. In it, his expert agreed with the defendant’s expert that he had not suffered post-traumatic stress disorder at all and that he had been deceitful in describing his symptoms. The solicitors expressed their surprise, and the expert admitted that she had not seen the other side’s report at the time of the conference, which was on the telephone. She said that the joint report did not really set out her views and she said that she was happy that it should be changed.

The solicitors asked the court if they could change expert, but permission was not given. Faced with an unsatisfactory joint report, the claim was settled for rather less than had been expected. The motorcyclist then sued the expert for negligence. The claim failed, because the judge was obliged to follow an earlier Court of Appeal decision that an expert was entitled to immunity from claims for negligence in the course of litigation. Leave was given however for appeal to the Supreme Court.

Expert witnesses have been given the privilege of immunity to make sure that they do not feel constrained to support their clients through thick and thin, despite having doubts about the strength of the case. It is a tradition that dates back more than 400 years, and it is one that two dissenting justices in the Supreme Court felt should continue.

But the majority of the Supreme Court justices decided that it was time for change. Their underlying philosophy was that every wrong should have a remedy, and any exception to that rule should be justified as being in the public interest. Immunity was not necessary to ensure that expert witnesses were honest in court. If the expert used his reasonable skill and care in giving advice to his client and then changed his mind when the full facts and opinion of other experts were available, there was no breach of duty. If the expert had been negligent in giving advice in the first place, there was no reason why a claim should not be made.

The lead judgment was given by Lord Phillips, but it was enthusiastically supported by Lord Dyson, who came across an expert or two when he was presiding judge in the Technology and Construction Court (TCC).

There has been an explosion of blog comments from lawyers on this in the days since the judgment on 30 March. Some think that there will be a revival of the “hired gun” style of expert witness, determined to fight vigorously for the client - even if their understanding of the facts changes, simply because they fear being sued. This type of expert witness does still exist, but they have become rarer in the construction courts as judges have been increasingly robust in criticising such behaviour. After all, it is not good for your practice to have comment in the law reports that you are unreliable. This is likely to remain an effective disincentive to the over-eager expert.

Others think that there will be an explosion of litigation with virtually every unsuccessful litigant blaming the expert and having a go to recover outlay on costs and damages. This also seems unlikely. It didn’t happen when barristers lost their similar immunity. On the other hand it may mean that expert witnesses take real care to avoid making mistakes in a case in which their opinion is a deciding factor. If this decision encourages experts to read what they are signing and only agree things that they really agree, the whole court process will benefit. That is particularly true in the TCC where so many cases hinge on expert opinion.

One effect will be interesting to monitor. Will insurance premiums go up? They shouldn’t, but they probably will.

John Redmond is a consultant at Osborne Clarke