This was a significant and well reported patent case which was determined in the Intellectual Property List within the High Court last autumn.   

The technical aspects of the case required significant expert input from the panel involved.  The cross-examinations performed by leading Counsel for the parties were lengthy and complicated.  This led to confusion over what evidence was given when the transcripts were re-visited on subsequent trial days. The case shows how consideration should be given to experts who are being cross-examined so not to overload them with questions and information on the stand.

The expert paediatrician in this case misidentified and confused twins when reading the primary medical disclose. This fundamental error was of seminal importance in this case because the twins had very different birth and post-birth experiences, with one being much weaker and more vulnerable than the other.  The judge noted that the cross-examination of the expert was nothing short of a demolition of the expert’s evidence.

LB Croydon v D (critical scrutiny of the paedeatric overview)

The complexities of this case required both parties to engage expert quantity surveyors.  Both sides approached their instructions to their expert from different angles which caused difficulties at trial.  This explained why the valuations were worlds apart (or as the judge commented they had a “manifestly excessive difference”) and needed some careful scrutiny and assessment by the judge. Whilst the approach of examining both valuations is very case specific, there are some fundamental tests which can be taken away.  An objective test was used several times as a benchmark looking at the scope of works that a ‘reasonable owner’ or ‘purchaser’ would require.  The key legal issue of “proportionality” was also visited frequently throughout the assessment of valuations. 

Iya Patarkatsishvili & Anor v William Woodward-Fisher [2025] EWHC 265 (Ch)

The judge in this claim for professional negligence struck out a witness statement which contained paragraphs which were pure opinion, made by the witness as a self-proclaimed expert, noting that it was expert evidence by the back door, in contravention of CPR Part 35 and plainly abusive. 

Israel Russell v Barry Coulter [2025] EWHC 493 (KB)

While the Judge in this extradition appeal ultimately reached the same conclusion as the District Court Judge, and dismissed the appeal, he pointed out significant deficiencies in how the District Court Judge had treated the expert psychological evidence.

The judge preferred the evidence of the Claimant's expert because of the Defendant's expert’s approach to his task as expert, his confusion over the proper approach to what prior art was and was not in the common general knowledge, the number of assertions he made which he was forced to resile from as incorrect, and his failure to acknowledge a key fact.

The judge found that the forensic accounting expert’s approach of forming an opinion as to the value of the Company, then carrying out a detailed calculation and only if it matches his initial opinion accepting it, undermined the credibility and reliability of his opinion as to the value of the Company.

In the last podcast for 2024, we look back at the ten key issues for expert witnesses that we've seen over the course of 2024, and highlight the ten things to look out for in 2025. From knowing and complying with your duties, to reevaluating and changing you opinion and handling fundamental dishonesty, this year in review has it all. 

The judge found that the evidence of the claimants' psychological expert fell well below the standard to be expected of a competent expert witness, both as to form and as to substance.

Rashpal Samrai & Ors v Rajinder Kalia [2024] EWHC 3143 (KB)

In this Bermudan case, the appellant successfully appealed to the Judicial Committee of the Privy Council to have his convictions quashed because of errors in the collection, examination and interpretation of the DNA expert evidence used in the trial.

Julian Washington (Appellant) v The King (Respondent) (Bermuda) [2024] UKPC 34