The use of experts to inform legal proceedings is nothing new. The ancient Romans, for example, occasionally employed handwriting specialists and land surveyors as legal experts. However, the systematic use of expert witnesses and the routine admissibility of their testimony and subject matter expertise, really began to develop properly from around 250 years ago.
The model we recognise today whereby an expert witness is permitted to testify in court and provide opinion evidence can be traced to 1772. In the case of Folkes v. Chadd, a civil engineer by the name of John Smeaton, was instructed to provide testimony about technical issues concerning the development of a harbour at Wells-Next-The-Sea, in Norfolk.
The decision by the Court in 1772 to use Smeaton’s opinion evidence, to inform its substantive decision, was a starting point for a continuous expansion of expert testimony in court and other proceedings.
For over 250 years, the role of expert witness steadily evolved. Any person who possesses knowledge and/or experience of a subject, over and above that of a layman, can act as an expert witness. For a long time, being manifestly proficient in a subject area, was all the qualification someone needed to be an expert witness in court or other proceedings.
However, in more recent times, evolution has turned to revolution. The skills required of expert witnesses have become far more wide-ranging, to the extent that just being a credible subject-matter expert is no longer enough. Following the Supreme Court Judgment in Jones v Kaney in 2011 expert witnesses can now be sued in negligence. This judgment and more recent judicial criticism of expert witnesses, who engaged in inappropriate fee arrangements with clients or revealed themselves to be out and out advocates, has focussed attention on a fundamental truth about what the role entails today.
The reality is that being a technical expert does not necessarily make someone a good expert witness. To be both a dependable expert witness and avoid getting into difficulties with instructing parties and Courts alike, experts are required to be competent in a wide range of other skills too.
Expert’s today must be fully conversant with, and comply with, increasingly intricate legal and procedural formalities that have become attached to the role.
They must understand, and be able to carry out, the function in accordance with applicable rules and Court directions. They must be constantly aware that their primary duty is to assist the Court and that they are not there to promote the case of either party. Their task is to help the Court understand their specialist subject to the extent that the Court can reach an informed judgment on the substantive matter that is before it.
Barristers for the instructing party will coax an expert into providing accurate and admissible evidence that will support their client’s case. the challenge for experts is to remain within their area of expertise and be open and honest, even if it harms the instructing party’s case. Barristers for the other side will interrogate experts robustly, often with the objective to undermine their credibility and challenge their opinions.
Experts in Courts today need also to be able to respond effectively to contrary opinions submitted by others who profess expertise in the same subject and withstand direct scrutiny from the judge. It is essential that they communicate information, and give answers to questions, effectively to people who do not have their high level of expertise and will not necessarily understand technical language associated with the expert’s subject. Their communication skills will often need to cover both written and verbal.
Experts should know how to dress for Court and how to address the Court. Even when they have acquired all the above qualities and qualifications. they will need to demonstrate the single most important trait required of an expert witness. They must always behave ethically.
There is no legal duty for expert witnesses to be trained in how to present evidence, or write reports, though experts will invariably be required to confirm in their reports that they understand, and comply with, their duties to the Court.
My employer, the Royal Institution of Chartered Surveyors (RICS), like other professional regulatory bodies, is responsible for ensuring its members act professionally, and this includes when they undertake the role of expert witness.
Chartered surveyors who act as experts in Court or other proceedings must not only comply with legal requirements for expert witnesses, but also a mandatory RICS professional practice statement. RICS publishes guidance and encourages its members to undertake training and attain an RICS Expert Witness Certificate. All of this is intended to give confidence to instructing parties and Courts that they can depend on RICS members to know how to discharge the role of expert witness to a high standard.
In these days, experts who are chartered surveyors, lawyers, doctors, etc. must demonstrate professional and ethical behaviours that are expected from people who are members of their relevant professional bodies. Poor conduct by experts may not only create problems for them, but it will also often reflect on their peers. Judicial criticism of expert witnesses happens. When it does it inevitably throws a spotlight on the individual expert. It can also give rise to wider concerns about the behaviour of other professionals working in the same sector or industry.
Martin Burns
RICS, Head of ADR Research and Development
26 August 2025