How expert witnesses came to shape modern justice

It was not until the 18th century that matters began to be structured more formally, with Lord Mansfield appointed as Lord Chief Justice in 1756. Mansfield introduced the concept of ‘special juries’ being formed to assist in resolving disputes. It was during Mansfield’s time that the first evidence can be seen of opinion evidence being admitted in common law. This was the case of Folkes v Chadd (1782), or the Wells Harbour case. The dispute involved the position of an artificial embankment and whether it created a nuisance by blocking the harbour way at Wells.

Mansfield is quoted as declaring: “The cause of decay of the harbour is a matter of science … men such as Mr Smeaton alone can judge. Therefore, we are of the opinion that his judgment, formed on facts, was very proper evidence."

Opinions based on suitable ‘experts’ continued to be deemed admissible through the late 18th century and into the 19th century. In the case of M’Naghten (1843), Chief Justice Tindall ruled that where facts were in dispute, the courts required detailed hypothetical questions in the examination of an expert.

However, the use of experts was not without its opposition at this time. In Lord Abinger v Ashton, the Master of the Rolls stated his distrust of so-called experts, complaining that they were biased to one side, calling them and saw themselves as paid agents of those who employed them. He echoes this in the case of Thorn v Worthing Skating Rink (1876) where, with respect to the Court appointing an expert, it meant finding an unbiased expert, which was challenging.

And so, a rather uneasy relationship between expert and Court continued for many decades until the leading case of the Ikarian Reefer (1993). The Ikarian Reefer case concerned a shipping dispute where it was alleged that a ship had been damaged with the owner’s knowledge in anticipation of triggering a marine insurance payout. This case relied on expert testimony with Cresswell J laying out the rules for expert engagement and setting the initial pathway for today, with the overriding comment that “expert evidence presented to the Court should be, and seen to be, the independent product of the expert uninfluenced as to form or content by the exigencies of litigation”. 

Shortly following this case, a report was issued by Lord Wolf in 1996 addressing required reforms. This came into effect in 1999 in the form of the Civil Procedure Rules, which govern expert witnesses to this day, Part 35 covering Civil cases and Part 25 covering Family cases.

The immunity of experts from liability has itself been a matter for debate. In 2005, a high-profile case involving Sir Roy Meadow, where his erroneous expert testimony led to an innocent mother being convicted for her children’s death, eventually saw him granted immunity although the Master of the Rolls disagreed. However, in the case of Jones v Kaney in 2011, the UK Supreme Court ruled that experts should not be immune where they have been shown to be negligent, reversing legislation that had effectively been in place for over 300 years. At the time, this brought up concerns that experts may now be overly cautious about committing to giving evidence. However, these concerns have been proved unfounded to this date.

The role of the Expert Witness has evolved significantly from its informal beginnings to become a cornerstone of modern legal proceedings. Once viewed with scepticism, expert testimony is now governed by clear rules that emphasise independence, impartiality, and relevance. While the relationship between experts and the courts has not always been straightforward, today’s framework ensures that expert evidence supports the pursuit of justice with clarity and credibility.