“(1) This section applies to evidence of the following kinds: … (c) evidence the reliability of which may be affected by self interest age or ill health, whether physical or mental, … (2) Where there is a jury, the court shall, unless there are good reasons for not doing so, (a) warn the jury that the evidence may be unreliable; (b) inform the jury of matters that may cause the evidence to be unreliable; and (c) warn the jury of the need for caution in determining whether to accept the evidence and the weight to be given to it.”
“Human evidence shares the frailties of those who give it. It is subject to many cross-currents such as partiality, prejudice, selfinterest and, above all, imagination and inaccuracy. Those are matters with which the jury, helped by cross-examination and common sense, must do their best. But when a witness through physical (in which I include mental) disease or abnormality is not capable of giving a true or reliable account to the jury, it must surely be allowable for medical science to reveal this vital hidden fact to them.”
“So, too, must it be allowable to call medical evidence of mental illness which makes a witness incapable of giving reliable evidence, whether through the existence of delusions or otherwise.”
“The prosecution say that a third aspect of their case is the description given by Mr Shirley, who saw a man fitting the description of Campbell …”