R -v-Pabon: A Warning on Expert Witnesses

Lucinda Murphy is a Trainee Solicitor in the Commercial Litigation de-partment at Howard Kennedy LLP
It is the duty of an expert witness to help the court on the matters within his expertise, as Halsbury said.

The expert witness in the recent case of R -v-Pabonwas more of a hin-drance than a help, as the Court of Appeal judgment noted. The case in-volved the appeal by one of the LIBOR defendants against his conviction, said to be unsafe because of the failings of a “disastrous” expert witness for the serious Fraud Office (SFO). Although it is a criminal case, it serves as a reminder and warning in the civil context on the role and duty of an expert witness. Those instructing the expert must also be conscious of their role and duty in this too.

The Facts

The SFO’s expert witness, Rowe, had signed documents stating that he had complied with his duties when he knew he hadn’t; he had failed to report with any detail or accuracy as to how he reached his opinions; he secretly consulted, by text and email, with a number of undisclosed advi-sors on the contents of his report; he blatantly disregarded the express warning of a trial judge not to discuss his evidence and did just that; and he knowingly gave evidence about matters outside his area of compe-tence. It was argued Pabon’s conviction was unsafe because the duty resting on an expert witness is so fundamental that where it is abused, the entire process is affected.

The Court of Appeal took a grave view of Rowe’s failure to comply with his basic duties as an expert, but ultimately Pabon’s conviction was safe as the key issue at trial was dishonesty and Rowe’s evidence did not im-pact on that.

In the end, the appeal was therefore dismissed but this should not detract from the Judges’ scathing criticisms of the appalling expert evidence.
Allowance was given to the SFO as Rowe had given evidence in LIBOR tri-als twice previously, without his expertise being questioned. However the SFO was asked whether it had learned lessons from the embarrassing de-bacle and there was a stern warning for all those instructing expert wit-nesses to satisfy themselves as to the witness.

Jones v Kaney [2011] UKSC 13

One step beyond an unsatisfactory expert witness, is a negligent one, which was discussed by the Supreme Court in Jones v Kaney. This case reviewed the immunity of experts to claims for professional negli-gence. Prior to this, experts were generally protected from being sued by their discontent instructing parties because they enjoyed a long established rule which said that, except for reasons of bad faith, no witness could be sued for anything said or done in the ordinary course of court proceedings. Jones v Kaney changed this and since then, an instructing party can bring a claim against an expert that has acted negligently or dishonestly.


Rowe’s failings were many but, crucially, he gave evidence outside his expertise and secretly relied on and consulted others in order to give evidence on those areas beyond his own expertise. It should never have got that far.

Both parties have an equal role to play; the expert and those in-structing him. The Court of Appeal added in the postscript to the R-v-Pabon Judgment that those instructing an expert witness, must “satisfy themselves as to the witness’ expertise and to engage (difficult though it sometimes may be) an expert of a suitable calibre”. To state the obvious, expert evidence must be expert! It can become an embarrassment for a party to find during trial that their expert is not only not particularly helpful, but is in fact significantly unhelpful and undermining to their case. Those instructing the expert cannot be complacent and rely on the fact that an expert has been previously used in the same or a similar case. There should be continual and up-dated assurance, by thorough research, on those they intend to in-struct.

Similarly, the expert must accurately disclose the areas of his exper-tise; in particular the boundaries of his expertise and when something falls outside of this. While an expert may research matters to boost their opinion, this cannot be used as the basis to become an expert on that matter.

As the SFO undertook to do after R -v-Pabon, those instructing expert witnesses should review their procedures and instructions to ensure the expert witness is fully aware of their obligations to the Court and has the necessary expertise. The fact that an expert witness has signed a declaration regarding their conduct and duty as an expert cannot necessarily be relied on. Experts must familiarise themselves with their duty and the conduct expected of them. They cannot rely on the fact that they may have read such documentation when giving evidence in previous cases or even the very living of evidence in pre-vious cases.

An expert must assist the Court. The instructing party and the expert must be fully cognizant of the expert’s duties and ensure that they are complied with, failing which an otherwise strong case might be fatally undermined.