23 / 100

An embarrassing debacle

Apr 2023

An embarrassing debacle


This is a UK case which involved a claim for fraud against various traders at Barclays Bank by the UK Serious Fraud Office (“SFO”).  It was alleged the traders rigged the London Inter-Bank Offered Rate (“LIBOR”).  They were charged by the SFO and convicted.


Error – Expert witness debacle. Expert Opinion and Testimony from apparently experienced expert

Relevant at the trial was the expert evidence from the SFO’s expert, a Mr R, regarding the workings of an investment bank.

A retrial was ordered on the basis of various failings by Mr R as an expert witness, and the conviction was unsafe.   


The retrial (and subsequent appeal of the retrial) found that Mr R’s failings as an expert were extensive.  They included1:

    1. Signing of documents stating that he had complied with his duties (including reading the relevant procedure rules) when he knew he hadn’t in fact done so.
    2. Failed to report with any detail or accuracy as to how he reached his opinions.
    3. Blatantly disregarding the directions of the trial judge during the course of the trial. In particular, during a break in the giving of evidence, and despite a specific request of the judge not to discuss his evidence with anyone, Mr R contacted a colleague to ask for her input on certain technical points.
    4. Knowingly gave evidence about matters outside his area of competence (such as in relation certain bank trading activities).
    5. He did not inform the SFO, or the Court, of the limits of his expertise.
    6. Secretly consulting with a number of undisclosed advisors in relation to the assignment, primarily on the areas beyond his competence and expertise.

This information was not in fact available at the time of the original trial, and only became evident thereafter.  Had this information been available it would have permitted “devastating cross-examination” of Mr R2, and indeed did so at the retrial.

These were deeply troubling failings that bring the system of justice into disrepute3 and the court took a very grave view of Mr R’s conduct4

However, despite these failings, the court was wholly unable to make the causal link between Mr R’s failings and the issue of the appellant’s dishonesty, which was the key focus of the trial.  The issue of the appellant’s dishonesty was wholly unaffected by Mr R’s evidence, even considering Mr R’s presentation in the round. Accordingly, the safety of the appellant’s conviction was to stand5.

Despite the conviction standing in this case, some other traders in related but separate proceedings also sought retrials in those separate proceedings.  These were granted on the basis of Mr R’s failings as an expert.  The traders were acquitted at the retrials6


Sanction by Court

Despite the grave view of Mr R’s conduct, the court would not be drawn on questions of sanction for Mr R, but did highlight his failings here for the consideration of others7.

The court specifically went on to say that the instruction of Mr R “turned into an embarrassing debacle for the SFO, all the more so, given the high-profile nature of these cases and notwithstanding that, in the event, it has had no impact on the outcome in this case.8

The court pressed the SFO’s counsel for details of any internal reviews on lessons learnt from this, and despite this internal review, the SFO undertook to look again at the matter to see whether there was any way in which it could reinforce expert witnesses’ awareness of their obligations.

Surprisingly, it transpired that this was the third time that Mr R had given evidence in LIBOR trials and the first time any questions concerning his expertise had apparently arisen. However, the court found “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 calibre9.


    Most obviously this case stands as a reminder of what expert witnesses should not do.  It highlights the many and varied ways in which expert witnesses may fail (and indeed sometimes do fail) in their various duties.

    Perhaps more interestingly this case stands as an example of the effects of a failure of an expert witness to reach maintain the rigorous standards rightly expected of them.  Here the expert’s failings led to the potentially avoidable time and expense of a re-trial (both in this case, and other related cases) and appeal. 

    Such failings will inevitably lead to reputational damage to the expert himself, and may also lead to sanction by the relevant regulatory or professional body – a point the court went to some pains to suggest, while of course noting that the details of the sanction was not a matter for the court itself to decide10.

    The reputational damage to the party itself from an expert’s failings is also a point which the court went to considerable length to address in the judgement.  Parties who engage experts must be sure that the experts themselves are in fact of sufficient competence and expertise, and if the party fails to determine this the party itself may be liable to censure11

    Implicit within this is also the reflection of such a debacle on the party’s legal team.  While not specifically addressed by the court, a legal team who relies on a manifestly incompetent expert witness at a trial may also find itself facing difficult questions beyond the issues and matters of the case itself, not to mention the reputational damage in being associated which such a shambles. 

    To see how we can potentially assist in the training of expert witnesses, including training on expert witness duties, please contact us.

    1 At paras 29 and 58.
    2 At para 29.
    3 At para 29.
    4 At para 58.
    5 At para 73.
    6 At para 6 and 29.
    7 At para 58.
    8 At para 76.
    9 At para 77.
    10 At para 58.
    11 At para 77.

    Subscribe to our newsletter

    Sign up here to get the latest news, updates
    and tips directly to your inbox.

    You have Successfully Subscribed!