"The first arises if it emerges that there may have been a complete repudiation of the oath taken by the jurors to try the case according to the evidence ... The second exception arises in cases where extraneous material has been introduced into the jury deliberations ... Examples are provided by earlier decisions of this court. They include telephone calls into or out of the jury room, papers mistakenly included in the jury bundle, discussions between jurors and relatives or friends about the case, and in recent years, information derived by one or more jurors from the internet ... Where the complaint is made that the jury has considered non-evidential material, the court is entitled to examine the evidence (possibly after investigation by the CCRC) to ascertain the facts."
"It is easy, but superficial, to dismiss these rules as purely technical or procedural. In truth, they reflect something much more fundamental. If material is obtained or used by the jury privately, whether before or after retirement, two linked principles, bedrocks of the administration of criminal justice, and indeed the rule of law, are contravened. The first is open justice, that the defendant in particular, but the public too, is entitled to know of the evidential material considered by the decision making body; so indeed should everyone with a responsibility for the outcome of the trial, including counsel and the judge, and in an appropriate case, the Court of Appeal Criminal Division. This leads to the second principle, the entitlement of both the prosecution and the defence to a fair opportunity to address all the material considered by the jury when reaching its verdict. Such an opportunity is essential to our concept of a fair trial. These principles are too basic to require elaboration. Occasionally, however, we need to remind ourselves of them."