King's / Queen's Bench Division of the High Court

[2025] EWHC 2025 (KB)

Fecha: 31-Jul-2025

The claimant’s expert witness – Mr Michael Thompson (“Mr Thompson”)

The claimant’s expert witness – Mr Michael Thompson (“Mr Thompson”)

29.

Mr Thompson is a retired general and colorectal surgeon with over 25 years’ experience in a District General Hospital. In evidence-in-chief he said that his last major surgery was in 2019. In cross-examination he said that by the 1990’s he was “pretty well exclusively a colorectal surgeon” mainly cancer but also haemorrhoids. However, he then said that he had not done many haemorrhoidectomies and had never done a ligature haemorrhoidectomy. He also said that from 2009 he was doing “very little operating on haemorrhoids” but then added that after 2010 he did no operating on haemorrhoids at all. He agreed that it was “a reasonable point” that it was difficult for him to identify the standard of a reasonably competent haemorrhoid surgeon in 2019.

30.

My view of Mr Thompson as a witness was that his evidence was based on limited experience or expertise. Unfortunately, during cross-examination it emerged that in several instances he had not acted in accordance with his duties as an expert under Civil Practice Direction 35 (“PD 35”). I observe here that the General Requirements for Expert Evidence contained in PD 35 are as follows:

Expert Evidence – General Requirements

2.1

Expert evidence should be the independent product of the expert uninfluenced by the pressures of litigation.

2.2

Experts should assist the court by providing objective, unbiased opinions on matters within their expertise, and should not assume the role of an advocate.

2.3

Experts should consider all material facts, including those which might detract from their opinions.

2.4

Experts should make it clear –

(a)

when a question or issue falls outside their expertise; and

(b)

when they are not able to reach a definite opinion, for example because they have insufficient information.

2.5

If, after producing a report, an expert’s view changes on any material matter, such change of view should be communicated to all the parties without delay, and when appropriate to the court.

31.

One example of this is that in cross-examination, Mr Thompson was asked why his witness statement dated 21 July 2021 referred to him having read the claimant and defendant’s witness evidence when this was only served in April 2024. He said that when the witness evidence was served, he did have regard to it but his opinion had not changed since he wrote this 2021 report. This does not however explain how he was able to have regard to witness evidence in July 2021 when these statements did not even come into existence until 2024. It was also pointed out to him that neither this expert report, nor his subsequent report dated 4 February 2022 made any reference to the defendant’s case and nor had he analysed the defendant’s case. He accepted this and also accepted that under PD 35 he was under a duty to assess the arguments on both sides and weigh them up fairly – which he believed he had (even though he had not addressed the defendant’s case at all in either of his reports). There are other examples which are dealt with in the body of this judgment below.