R v Davis [2008] UKHL 36, [2008] All ER (D) 222 (Jun)
(i) There is a presumption in favour of open justice and confrontation of a defendant by his accuser.
(ii) It is possible in principle to allow departures from the basic rule of open justice, but a clear case of necessity has to be made out.
(iii) The court should be sufficiently satisfied that the witness’s reluctance to give evidence in the ordinary manner is genuine and that the extent of his fear justifies a degree of anonymity.
(iv) Anonymising expedients may include the withholding of the witness’s name and address, screening of the witness from the defendant and the public, screening from the defendant’s legal advisers, disguising of the witness’s voice from the defendant and the public and disguising of the voice from the legal advisers.
(v) The more of these expedients the court might consider adopting, the stronger the case must be for invading the principle of open justice. Determination of the question depends upon balancing to ensure that the trial continues to be fair.
(vi) An important consideration is the relative importance of the witness’s testimony in the prosecution case. If it constitutes the sole or decisive evidence against the defendant, anonymising which prevents or unduly hinders the defendant and his advisers from taking steps to undermine the credit of the witness is most likely to operate unfairly. It is a question of fact in any given case what, if any, measures would be compatible with the fairness of the trial. Courts trying criminal cases should not be over-ready to resort to such measures. Very great care must be taken in each and every case to ensure that attention is paid to the letter and spirit of the European Convention on Human Rights (the Convention). As a general rule it is unlikely that the trial will be fair if a very substantial degree of anonymising of evidence is permitted where the testimony of the witnesses concerned constitutes the sole or decisive evidence implicating the defendant (Lord Carswell at 59).