Summary and implications

In a landmark ruling this year, the Supreme Court abolished a 400 year old rule giving expert witnesses immunity from claims for breach of duty to their instructing client for the evidence they give in court, or for the views they express in anticipation of court proceedings1.  

Expert witnesses can now be sued for breach of contract and/or negligence.  

The decision should mean:  

  • Experts should have a heightened awareness of the risks of pitching their initial views on the merits of a client’s case too high or too rigidly;  
  • Experts must avoid taking unsustainable positions simply to give their client a more favourable potential outcome;  
  • Genuine opinions will help clients to reach difficult decisions in litigation sooner;  
  • The cost of instructing experts may increase to reflect the additional cost to the experts themselves of obtaining insurance to cover the risk of negligence claims.  

Background to the rule

Witness immunity dates back over 400 years. It originally related to experts giving evidence in court but was extended to cover reports and work preliminary to trial, including joint meetings of experts.  

The primary reason for the rule was the concern that an expert witness might be reluctant to give evidence to the court which was contrary to his instructing client’s interests if there was a risk he could be sued, even if this was in breach of his duty to the court.  

It was also thought that witnesses could be exposed to vexatious claims by disgruntled litigants if the immunity did not exist and this in turn would affect the supply of expert witnesses because experts would be reluctant to take on this risk.  

Jones v Kaney1  

Jones v Kaney concerned a road traffic accident claim in which Mr Jones instructed Dr Kaney, a clinical psychologist, to prepare a report for the court.  

Dr Kaney subsequently agreed a joint statement for the court prepared by the defendant’s expert. She signed the statement without comment or amendment and later admitted that the statement did not reflect what she had discussed with her counterpart, and that she had signed it under pressure from him.

The joint statement was highly damaging to Mr Jones’ case, forcing him to settle his claim for a much lower sum. Mr Jones sued Dr Kaney for negligence and she pleaded expert immunity.  

Issues for the Supreme Court

The narrow issue before the Supreme Court in this case was whether the immunity extended to the preparation of a joint statement for the court. However, the court considered the matter to be of such importance that it looked afresh at the whole issue of whether public policy justified giving an expert witness immunity from liability in negligence.

A similar rule applied to advocates and this was abolished in 2002. The Supreme Court found that there was no difference between an advocate and an expert witness; both owe a duty of care to their client, as well as an overriding duty to the court (see box).

The position of experts is made plain in the Civil Procedure Rules which require any report to state that the expert has complied with his duty to the court, and an expert is retained on the basis he will perform his function in accordance with the Civil Procedure Rules.  

The court thought it would be difficult for a party to mount a claim against an expert without a credible case that the expert had been negligent. Therefore, the risk of vexatious or multiplicity of claims was unlikely to arise.  

The argument that experts would be deterred from acting if immunity was abolished was also unsuccessful.

What does the ruling mean?

The fact that expert witnesses can now be subject to a claim in negligence should mean better quality advice, with experts ensuring they give well-thought out opinions.  

As Lord Justice Brown commented, the consequence of removing expert witness immunity “will be a sharpened awareness of the risks of pitching their initial views of the merits of their client’s case too high or too inflexibly lest these views come to expose and embarrass them at a later date”.

This should mean that parties know the real strength of their case at an early stage and are, therefore, better equipped to decide whether or not to litigate, and where the boundaries of settlement lie.

And for experts?

The vast majority of expert witnesses act in a highly professional way and will have little to fear by this ruling, though in practice they are likely to face increased professional indemnity insurance premiums to cover the additional risk of being sued.