Preece v. H.M. Advocate - PDF document

Preece v. H.M. Advocate [1981] Crim.L.R. 783 High Court of Justiciary, Edinburgh : Lord Justice - General (Emslie), Lords Cameron and Stott: June 19, 1981 Scotland Reference by Secretary of State - Criminal Procedure (Scotlan d) Act 1975, s. 263 (1) (a) - murder by strangulation - expert evidence - reassessment in the light of new scientific evidence - standard expected of expert - P a long distance lorry driver was convicted by majority of the murder by strangulation in a lorry in Scotland of a woman whose body was found buried on the English side of the Border near Carlisle, his conviction later being sustained on appeal which challenged the sufficiency of the whole evidence. At his trial in Edinburgh in 1972 the principal evidence against P had been scientific evidence of blood and seminal stains, hairs, fibres, grass seeds and other material said to link P with the victim. The scientific evidence was given mainly by Dr. C a forensic scientist who made the tests corroborat ed by a junior colleague who carried out no tests himself. After P had been in prison for more than seven years questions were raised as to the quality of the scientific evidence and the scientific detachment of Dr. C and the case was referred back to the High Court under section 263 (1) (a ) of the 1975 Act on the allegations that Dr C had withheld evidence he should have given about the victim's blood group, had failed to disclose that stains he had tested were not isolated seminal stains but mixed semina l and vaginal stains, and had reached unwarrantable conclusions thereon. The High Court having heard afresh the evidence of Dr. C along with the evidence of six eminent forensic scientists on the limited serological aspects of the case found it established (a) that at the trial Dr. C had omitted from his written report and failed to mention in evidence the blood grouping and secretor status of the victim although he knew her to be Group A and probably a secretor (b) that he had unwarrantably professed to be able to distinguish from mixed seminal and vaginal staining that the grouping of the male contributor was Group A secretor, and (c) that there was no scientific support for Dr. C's claim that he could distinguish in the mixed staining the blood group subs tances derived from the male because these gave a stronger reaction than would have been characteristic of such substances emanating from the female: and Dr. C's evidence fell short of the standards of accuracy and objectivity required of an expert witness . Held, that had the jury heard the new evidence they must have found Dr. C to be discredited as a scientific witness and that accordingly the whole of the scientific evidence he gave would have been regarded as unreliable; and the appeal must be allowed a nd the conviction quashed. For the appellant: D.B. Weir Q.C., W.F. Lunny (instructed by Scott Miller, S.S.C., Edinburgh.) For the Crown: Ranald N. Maclean Q.C. (instructed by W.G. Chalmers, Crown Agent). [Note and commentary by Alastair R. Brownlie.] Commentary: Only a few cases have been referred by the Secretary of State for Scotland to the High Court. The first and most famous was Slater v. H.M. Adv., 1928 J.C. 94, which following a belated attack on the judge's charge to the jury resulted in Slater's release from prison after nearly 20 years. In Gallacher v. H.M. Adv., 1951 J.C. 38, the court refused to allow new evidence because they were not satisfied that it would have produced a different verdict. In Higgins v. H.M. Adv., 1956 J.C. 69, the test for allowing such evidence was settled as being that it must have produced a different verdict had it been given at the trial. The peculiarity of the present case is that it was referred because of suggestions that the expert evidence at the trial had not been given properly. From reports it seems that the blood group evidence was virtually untested at the trial, was not even mentioned by the judge in his careful charge to the jury despite the employment by the defence of a for ensic pathologist and full legal representation for the accused, and was not in issue in the appeal. The recall of an expert after eight years to be confronted by a galaxy of leaders in his own specialty and subjected to many hours of cross - examination in a glare of publicity in a situation where he was both unrepresented and attacked as to his honesty and his capabilities was an occurrence without parallel in Scottish legal history which must fill every past and prospective expert witness with alarm. The law's requirements of an expert have hitherto been that he shall give his evidence to the best of his ability on his special subject in a fair and unbiased manner making a full and frank disclosure so as to provide the court with the material necessary to enable it to come to a reasoned decision on the merits of the scientific issue - Davie v. Magistrates of Edinburgh, 1953 S.C. 34 (a civil case quoted with apparent approval as applying to English law by Cross on Evidence). The present case reveals how ex pert evidence poses special problems for the court, for the parties and not least for the expert himself. In Scotland it is customary in criminal cases involving medical or scientific evidence for the experts to prepare and make available a joint report summarising their evidence. In due course the witness is examined like any other witness on the basis of this report and cross - examined as on any other evidence. Had the prosecutor of the court in the Preece case inquired of the witness what the victim's b lood group was, that matter would have been instantly clarified. The defence of course have no need to repair the omissions of the Crown but it is necessary to raise a matter at some stage if its absence is to be founded upon. There is no requirement tha t experts must supply written reports though if they do these should doubtless be as complete as reasonably possible. It may be that in view of the court's strictures witnesses will in future be more reluctant to provide written reports. Since their verbal evidence is given like any other by their response to questions the court's observations of the expert in this case that "he remained silent on this matter in the witness box" and that "he deprived the defence and the court of the means whereby they could have been called in question" emphasise the enormously high standard called for in written reports. In this case the expert was not asked an obvious question by the Crown or by anyone else although the Crown were aware of the victim's blood group. Does th e defence not, like the court, have a duty to try to follow the logic of the scientific evidence? To require an expert witness to cover the essential facts in his evidence and at the same time to supply the material wherewith to question its validity is to ask a great deal. Similarly with the experts's claim in this caseto differentiate the male and female elements in the stains. Had this been cross - examined at the trial the issue would have been before the jury and would have been resolved. For the first t ime it appears that the High Court is spelling out the supreme requirements for the expert, namely that he shall not only give his evidence to the best of his ability but also supply a critique of that evidence drawing attention to its weaknesses as well a s its strengths. Reforms of this kind were desiderated by Sir Roger Ormrod in "Scientific Evidence in Court" [1968] Crim.L.R. 240 where he recommends the adoption by scientific witnesses of something akin to the conventions of the Bar - "it should be a rigorous obligation on all experts to give the court as clearly as they can the limits of accuracy of their evidence, whether it is experimental or theoretical, and to disclose, if it be the fact, that other views exist in their profession. It should also be their duty to the court to indicate what inferences cannot properly be drawn from their evidence." These demanding requirements now apparently finding application in Scots law are bound to reopen the question whether the Scottish arrangements for deal ing with expert evidence within the adversary system are adequate and whether the system can operate where the defence play no part in testing the evidence or seeking to expose its weakness illogicality or bias. It would be unfortunate indeed if at a time when the amazingly sophisticated contributions of science - especially in the field of blood grouping - are becoming available to court of law the range of this evidence were reduced because of excessively high demands made upon scientific witnesses.