Matthew Scott’s “Barrister Blogger” blog is always an interesting read.  His latest post Expert witnesses: a crisis in the criminal courts  is essential reading for everyone involved in any type of litigation – and also for anyone who is an “expert witness”.


Matthew looks in detail at the

  • Report of the House of Lords Science and Technology Committee in the state of forensic science (scary reading).
  • The evidence of the “expert” Mr Ager in the recent failed trial on carbon credits (his conduct in the matter is extraordinary).
“The most alarming thing about the case, though, is not that Mr Ager was finally discovered to be an unclothed emperor, but the deference with which he had been treated in earlier cases, many of which had resulted in convictions. No-one seems very sure how many others there may have been. Mr Ager’s own estimate varied between about 20 and up to 50.
“For all the forensic expertise deployed on both sides in all those cases, Mr Ager was able to forge a career for himself, and it seems quite a well-paid one, as the “go-to” expert in carbon credit frauds. He was not rumbled until he was cross-examined by Narita Bahra QC in the latest case.”
  • The definition of an “expert” and area of expertise.
  • A detailed history of “less than honest” experts.
  • “Expert conmen” who, with qualifications bought from gave expert evidence as psychologists for over 30 years.
  • The “fake” doctor who earned £1.25 N as a bogus Harley Street doctor, with a steady income stream  coming from writing psychiatric reports for Immigration Tribunals.

Matthew also points out that even genuine experts become dangerous when they go outside their area of expertise.  Prof Roy Meadow in the conviction of Sally Clark provided unreliable statistical figures.


He points to the Court of Appeal decision in  Pabon, R v [2018] EWCA Crim 420. The expert witness for the prosecution, sought help in his evidence, during the course of his cross-examination.

    1. At the retrial, Rowe began his evidence on 9th March 2017. Pressed on the 9th and 10th March for disclosure by the defence, Rowe provided e-mail correspondence revealing that Mr Dominic O’Kane, a partner at Rowe’s firm and a part-time Professor of Pricing and Risk Financial Derivatives, had been responsible for drafting sections of Rowe’s report. This was not previously known.
    2. Furthermore, as Mr Kuhn recorded, the newly disclosed material revealed:
“5. ….that prior to April 2016 Mr Rowe had sent excerpts of the case papers to Ms Signe Biddle an interest rate derivatives trader and financial consultant at RBS and Mr Michael Zapties, Head of Rates Trading at HSBC and sought their assistance.
6. On Friday 10 March 2017 I contacted both Ms Biddle and Mr Zapties. I spoke with each by phone on 15 March 2017. They both said that they had been contacted by Mr Rowe and that in the course of their respective conversations he had neither told them that he was acting as an expert witness in a criminal trial, nor had he explained to them the caution which they should exercise in expressing an opinion.
7. On the weekend of the 11 March 2017 Mr Rowe provided further material to the SFO, in the form of text messages between Mr Rowe, Ms Biddle and Mr Zapties…..
8. From the additional disclosure it appeared that in the month prior to his giving evidence in the 2016 trial, Mr Rowe exchanged around 60 text messages with Ms Biddle and 27 text messages with Mr Zapties, as well as numerous emails with both them and Mr Nick Van Overstraeten, a third expert.”
  1. It may be noted that these exchanges included reference to STIR trading, a technical area which Rowe purported to cover when giving evidence.
  2. So far as concerns the exchanges between Rowe, Ms Biddle, Mr Zapties and Mr Van Overstraeten, matters do not end there. A remarkable feature of the newly disclosed material was the revelation that at the conclusion of the first day of his evidence at the trial – and having been expressly warned by the Judge not to discuss his evidence until it was concluded (see above) – Rowe went on to do just that.
  3. Within an hour, he sent a text to Ms Biddle, asking her to do “30 minutes (paid!) work tonight”, explaining that he needed an “interpretation of a STIR/OIS [Overnight Index Swap] email”. In the course of further exchanges with Ms Biddle, Rowe said “I don’t know the usual trades STIR people put on but I am learning”. Ms Biddle emphasised the importance of context, to which Mr Rowe agreed but added “…it doesn’t help when I have to explain a few emails and look knowledgeable”. On the same night, he remarked to Mr O’ Kane that he would do no more STIR cases; they would engage a STIR specialist, “as the mission has crept beyond where it was meant to for me”. In cross-examination at the retrial, he explained this by saying that he was “at the edge” of his expertise.
  4. Overall, between the conclusion of his evidence on the 13th April 2016 and resuming his evidence on the 14th April, Rowe exchanged some 26 texts or e-mails with Ms Biddle and Mr Zapties. When questioned on the 14th April, he made no mention of his contacts with Ms Biddle, Mr Zapties and Mr Van Overstraeten, notwithstanding, put at its lowest, their important contribution to the answers he gave.

This led the Court of Appeal to conclude

  1. Put bluntly, Rowe signally failed to comply with his basic duties as an expert. As will already be apparent, he signed declarations of truth and of understanding his disclosure duties, knowing that he had failed to comply with these obligations alternatively, at best, recklessly. He obscured the role Mr O’Kane had played in preparing his report. On the material available to us, he did not inform the SFO, or the Court, of the limits of his expertise. He strayed into areas in his evidence (in particular, STIR trading) when it was beyond his expertise (or, most charitably, at the outer edge of his expertise) – a matter glaringly revealed by his need to consult Ms Biddle, Mr Zapties and Mr Van Overstraeten. In this regard, he was no more than (in Bingham LJ’s words) an “enthusiastic amateur”. He flouted the Judge’s admonition not to discuss his evidence while he was still in the witness box. We take a grave view of Rowe’s conduct; questions of sanction are not for us, so we say no more of sanction but highlight his failings here for the consideration of others.


What is remarkable about that case is (1) The convictions were found to be unsafe; (2) this was the third time Rowe had given evidence :

  1. In fairness to the SFO, this was the third time that Rowe had given evidence in LIBOR trials and the first time any questions concerning his expertise had apparently arisen. Nonetheless, there is no room for complacency and this case stands as a stark reminder of the need for those instructing expert witnesses to satisfy themselves as to the witness’ expertise and to engage (difficult though it sometimes may be) an expert of a suitable calibre.


All of this, and more, is set out in Matthew’s post on the subject.  The issue of “worrying” experts is a universal issue in civil, criminal and family litigation.