Counsel misconduct: unfair or merely improper?
The Board’s assessment was (para 32):
“…their Lordships strongly deplore behaviour of this nature by prosecuting counsel. They should observe proper standards of decorum and courtesy in their conduct of the case, their treatment of the witnesses and the presentation of their addresses to the jury, as should all counsel in a trial. They should take care not to misrepresent the evidence given on either side or the case being made on behalf of the defence. They are of course entitled to make out as effectively as they can the prosecution case against the defendant, that he is guilty of the crime charged, for that is their proper function in an adversarial system. They have to be careful, however, not to allow vigour in presentation of the prosecution case to trespass into the area of unfairness by indulging in the type of behaviour exemplified by the cases which their Lordships have cited. Regrettably prosecuting counsel in the present case overstepped the mark on a number of occasions, and it would have been preferable if the judge had pulled him up earlier and made it clear that such behaviour was unacceptable. The issue is whether his departure from propriety was of such a nature as to deprive the appellants of a fair trial.”
This effort to state standards that apply to all counsel is, unfortunately, hindered by the Board’s deference to the view of the Court of Appeal here, as it acknowledged that it was “influenced by the fact that the Court of Appeal, with their knowledge of local conditions and culture, were of opinion that those remarks would not influence a jury in Trinidad to an extent which would make a trial unfair.” (para 34)
What, then, is the sort of influence on a jury that would make the trial unfair? The Board emphasised the approach in Randall v R  UKPC 19 that the overriding requirement is that the trial is fair, regardless of the strength of the evidence against the accused. As Lord Bingham said at para 28 of Randall:
“…the right of a criminal defendant to a fair trial is absolute. There will come a point when the departure from good practice is so gross, or so persistent, or so prejudicial, or so irremediable that an appellate court will have no choice but to condemn a trial as unfair and quash a conviction as unsafe, however strong the grounds for believing the defendant to be guilty. The right to a fair trial is one to be enjoyed by the guilty as well as the innocent, for a defendant is presumed to be innocent until proved to be otherwise in a fairly conducted trial.”
The exercise is one of weighing up the seriousness of the irregularities (29) as occurred in Bernard v The State  UKPC 34 (blogged here 11 May 2007). As I noted in discussing Bernard, the views of Lord Carswell (who delivered the Board’s judgment in that case and in the present case) may be changing, to emphasise that fairness does not turn on the strength of the prosecution case.
Given that we are not here to focus on the strength of the prosecution case, the sort of influence on the jury that is relevant is the risk that the jury will become prejudiced, partial, biased as a result of the misconduct.
That is why the Board was prepared to be influenced by the Court of Appeal’s view of the effect of the misconduct on the jury in this case.
This is not to say that, in countries with such juries, counsel may engage in misconduct as long as it falls short of causing unfairness. The Board made it clear that when it occurs, the judge should intervene to prevent its continuation.
The cases illustrate distinctions between robust but respectful speech (Benedetto v R  UKPC 27) and gratuitous and unpleasant remarks about defence counsel and improper vouching for the soundness of the prosecution case (Ramdhanie v The State (Trinidad and Tobago)  UKPC 47).
The idea that unfairness is unfairness, no matter whether it is caused by procedural error or the improper admission of evidence, which I have advanced in discussing Bernard v The State, is relevant to another aspect of the present case. A second ground of appeal was that new evidence undermined the ruling at voir dire that statements by two of the accused were admissible. Here the Board noted (37) “Given the strength of the prosecution case, the prospect that the material would have caused the jury to reach a different conclusion on these appellants' guilt is highly questionable.” This seems to be treating the (posited) improper admission of evidence as being cured by the strength of the prosecution case. This was obiter, as the new evidence was held not to have affected the correctness of the decision to rule the statements admissible.
It would have been more in keeping with an unfragmented concept of fairness to hold that the statements, if wrongly ruled admissible, did not cause the jury to be more disposed to accepting other prosecution evidence than it otherwise would have been.