Chapter 14: OPINION EVIDENCE
PDF version of Chapter 14
(1) GENERAL RULE AND RATIONALE
Historically, the rule against opinion is an offshoot of the hearsay rule. The general rule is that witnesses must state facts, not opinions and the rationale for the rule is that if they are allowed to give their opinions on ultimate issues, there is a serious danger that the jury will be unduly influenced.
However, Lord Mansfield CJ in 1782 in Folkes v Chadd formulated an exception to the general rule when he stated:
“On certain matters, such as those of science or art, upon which the court itself cannot form an opinion, special study, skill or experience being required for the purpose, “expert” witnesses may give evidence of their opinion.”
In that case, the question arose whether a certain bank, created for the purpose of preventing the sea overflowing certain meadows, contributed to the choking and decay of a certain harbour. The evidence of one Mr. Smeaton, a chartered engineer, was allowed.
Lawton LJ in R v Turner , relying on Lord Mansfield's formulation, described the purposes for which expert evidence could be deployed in the following terms:
“Opinions from knowledgeable persons about a man's personality and mental make-up play a part in many human judgments … An expert's opinion is admissible to furnish the court with scientific information which is likely to be outside the experience of a judge or jury. If on the proven facts a judge or jury can form their own conclusions without help, then the opinion of an expert is unnecessary. In such a case if it is given dressed up in scientific jargon it may make judgment more difficult. The fact that an expert witness has impressive scientific qualifications does not by that fact alone make his opinion on matters of human nature and behaviour within the limits of normality any more helpful than that of the jurors themselves; but there is a danger that they may think it does.”
In that case, the accused unsuccessfully pleaded provocation in an answer to a charge of murder and was not allowed to call a psychiatrist to testify that the deep relationship which subsisted with his deceased girlfriend was likely to cause an explosive outburst of rage at her confession of infidelity. However, in Lowery v R where Lowery and King were charged with a murder which must have been committed by either or both of them, King was allowed to call a psychiatrist to swear that he was less likely to have committed the crime than Lowery. The Privy Council held that the trial judge had acted properly.
According to Cross , one method of reconciling the two cases would be to treat the fact that Lowery put his character in issue as the reason for allowing the psychiatrist evidence to impugn the credibility of his testimony. Another method would be to treat Lowery as an aberrant case because in spite of the aberration the formulation in Turner had been accepted by the courts and the textwriters. The latter method is exemplified by the fact that opinions of experts are admissible on a variety of subjects such as handwriting , medical negligence , voice identification , ear print , DNA evidence and recovered memory (to mention a few) provided they are not on ultimate issues. It is not clear whether lip reading is expert evidence but opinions of experts on psychological profiles and psychological autopsies are inadmissible.
Expert and non-expert opinions are discussed in the sections that follow.
(2) EXPERT OPINION
Expert witnesses have been allowed to testify where the evidence to be adduced was not on the very issue to be decided by the court. Lord President Cooper in Davie v Edinburgh Magistrates described the duty of the expert as follows:
“The duty of the expert is to furnish the judge or jury with the necessary scientific criteria for testing the accuracy of their conclusions. Neither the judge nor the jury is bound by the views of the expert even if it is uncontradicted.”
This dictum, however, raises three questions: (i) Who is an expert?; (ii) What are the duties of an expert?; and (iii) What are the functions of the judge and jury? These questions are now answered in the lexical order they are posed.
The answer to the first question is in R v Silverlock where a solicitor for the prosecution who had for ten years, and quite apart from his professional work, given considerable study and attention to handwriting (especially to old parish registers and wills) was allowed to be called as an expert in order to prove by comparison with genuine letters that an advertisement was the handwriting of the accused. Lord Russell CJ said:
“It is true that the witness who is called upon to give evidence founded on a comparison of handwriting must be peritus ; he must be skilled in so doing; but we cannot say that he must have become peritus in the way of his business. The question is, is he peritus ? Is he skilled? Has he an adequate knowledge? … When once it is determined that evidence is admissible, the rest is merely a question of its value or weight, and that is entirely a question for the jury, who will attach more or less weight to it according as they believe the witness to be peritus .”
As suggested by Lawton LJ in Turner , the qualifications of the expert constitute an indicium of being peritus (i.e. skilled) but “this does not make his opinion on matters of human nature and behaviour within the limits of normality any more helpful than that of the jurors themselves.” The other indicium is the acquisition of experience on the issue in question over a period of time as in Silverlock .
The duties of an expert (the answer to the second question posed above) in criminal cases are those laid down at common law which are not different from those in the Civil Procedure Rules , which were stipulated to regulate the experts, first by keeping the costs down and second by guaranteeing their reliability. The duties of an expert (on which the CPR provide a gloss) were stated by Cresswell J in The Ikarian Reefer as follows:
1. Expert evidence presented to the court should be, and should be seen to be, the independent product of the expert influenced as to form or content by the exigencies of litigation.
2. Independent assistance should be provided to the court by way of objective unbiased opinion regarding matters within the expertise of the expert witness. An expert witness in the High Court should never assume the role of an advocate.
3. Facts or assumptions upon which the opinion was based should be stated together with material facts which could detract from the concluded opinion.
4. An expert witness should make it clear when a question or issue falls outside his expertise.
5. If the opinion was not properly researched because it was considered that insufficient data was available then that had to be stated with an indication that the opinion was provisional. If the witness could not assert that the report contained the truth, the whole truth and nothing but the truth then that qualification must be stated on the report.
6. If, after exchange of reports, an expert witness changed his mind on a material matter then the change of view should be communicated to the other side through the legal representatives without delay and, when appropriate, to the court.
7. Photographs, plans, survey reports and other documents referred to in the expert evidence had to be provided to the other side at the same time as the exchange of reports.
Finally, the role of the judge, the answer to the third question, was stated recently by Mackay J in XYZ v Schering Health Care Ltd. Re the Oral Contraception Litigation as follows:
(1) He must select the issues that appear to matter.
(2) He cannot transform himself into some kind of super-scientist with access to a level of expertise superior to those who have given the evidence.
(3) His role is to evaluate the evidence.
(He must also make clear to the jury that they were not bound by an expert witness's opinion. ) The role of the jury is to arrive at their own conclusion but when the evidence of experts differ on a trial by jury, the jury must decide the issue. On a trial by the judge sitting alone, the judge must decide as in XYZ v Schering Health Care Ltd. where the claimants were a number of women who alleged that they had suffered a variety of cardio-vascular injuries, which came under the description of venous-thrombolism, as a result of taking various brands of third generation combined oral contraceptives manufactured by the defendants whether the defendants were liable. The judge heard evidence from ten epidemiological experts who were largely irreconcilable in their differences and ruled that the case of the claimants was not proven on a balance of probabilities.
(3) EXPERT WITNESSES AND ULTIMATE ISSUES
An expert witness must be peritus (i.e. skilled or suitably qualified) and, according to the principle in Turner , must deal with matters beyond the jury's knowledge. He must not state his opinion on the ultimate issues. The problem, as we shall see, is that the prohibition on ultimate issues has been honoured more in the breach than the observance.
In DPP v A and BC Chewing Gum Ltd. the defendants were charged with contravening section 2 (1) of the Obscene Publications Act 1959 and section 1 (1) of the Obscene Publications Act 1964 in that they had for publication for gain certain obscene articles, part of which were sold together with the bubble gums, which would be seen and read by children of five years and over. The Divisional Court held, reversing the justices, that the evidence from child psychiatrists on the likely effects of the cards upon children of various ages was admissible at common law independent of the Act. The decision was doubted in DPP v Jordan where a bookseller charged with possessing obscene articles for publication for gain contrary to section 2 (1) of the Obscene Publications Act 1959 as amended, raised the defence of “public good” under the Act and sought to call expert evidence that the material in question would be psychologically beneficial to persons with abnormal sexual tendencies. The House of Lords held that the evidence had been rightly excluded. It seems, therefore, that the evidence of a psychiatrist under the Obscene Publications Act 1959 is admissible not to show that the materials in question are capable of corrupting and depraving the children (the ultimate issue) but to assist the jury in understanding the effects on the special audience to which they are directed.
It must be noted, however, that expert psychiatric testimony is admissible because it is legally necessary as in criminal cases where the plea of diminished responsibility is raised by the defence or where it will help the jury in its assessment of the pleas of insanity and automatism (whether of the sane or insane variety).
The inadmissibility of psychological and psychiatric evidence established in R v Chard has been confirmed in a shoal of cases. However, there is a blurred line of demarcation between cases where the evidence is rejected outright on the ground that it impinged on the ultimate issue and where it is admissible, in the luminous expression of Faquharson LJ, because “It would have been impossible for the layman to divine the data” presented in open court by the expert.
In view of the fact that the House of Lords in R v Camplin laid down as a matter of substantive criminal law that when determining an issue of provocation, a jury should take into consideration those factors including the age and physical characteristics of the accused which would affect the gravity of the provocation to him. Expert opinion has been rejected in R v Roberts because
“[T]he jury were aware of R's disabilities and characteristics which were highlighted during the judge's summing-up; and the medical evidence would not have added any enlightenment to what they already knew.”
However, judges are prepared to allow medical (be it psychological or psychiatric) evidence if, consonant with the principle in Turner , it is based on “scientific information which is … outside the experience of a judge or jury” or because “it would have been impossible for the layman to divine the data.” This is subject to two limitations: that the evidence does not infringe the hearsay rule and the rule against opinion.
In R v Maish it was held that if the defendant's I.Q. had been 69 or below and insofar as mental defectiveness was relevant expert evidence could have been admitted but because he had an I.Q. of 72, expert evidence was not necessary and was properly excluded. However, in Silcott, Braithwaite and Raghip , Hodgson J observed that it was artificial to draw a strict line at 69/70 I.Q. but the Court of Appeal took a different view. Raghip, a man chronologically aged 19 years and seven months at the date of interview which was subject to section 77 of the Police and Criminal Evidence Act 1984 (PACE) with a level of functioning equivalent to a child of nine years nine months and of reading of a child of six with an I.Q. of 74 could not be said to be normal. Faquharson LJ said it would have been impossible for the layman to divine that data from Raghip's performance in the witness box, still less his suggestibility. The Court held that in the context of the reliability of his confession pursuant to section 76 (2) (b) of PACE, psychological evidence was required to assist the jury and should have been admitted at his trial.
Again, in R v Toner the Court of Appeal held that the possible effect of a mild hypoglycaemic attack on negativing the accused's specific intent for attempted murder and wounding with intent was outside the experience of the jurors who should have been permitted to consider expert evidence.
Relevant expert evidence may still be excluded in civil and criminal proceedings because it infringes the hearsay rule or the rule against opinion. Although section 1 of the Civil Evidence Act 1995 (CEA 1995) renders admissible all forms of hearsay statements (whether they are first-hand or multiple hearsay) in civil proceedings, judges still have the power under section 4 (2) (the weight provisions) and section 14 (1) (exclusions on other grounds) of the CEA 1995 to exclude the evidence.
In criminal proceedings, section 30 of the Criminal Justice Act 1988 renders admissible the reports of experts whether or not they are called to give evidence with leave of court. This section remains in force after the enactment of the Criminal Justice Act 2003 (CJA 2003) . Section 127 of the CJA 2003 allows experts to give evidence of facts and opinions stated by others. It must be noted, however, that expert evidence may be excluded if it is infringes the hearsay rule and that section 78 of PACE applies across Part II, Chapter 2 of the CJA 203. For instance, in R v Weightman the Court of Appeal held that the evidence of a psychiatrist was inadmissible when its purpose was to tell the jury how a person not suffering from mental illness was likely to react to the stresses and strains of life. Again, in R v B (An Accused) the evidence of a child psychologist who had interviewed a sexually abused 12 year-old girl was declared inadmissible. McMullin J said:
“I think that the challenged evidence is inadmissible for two reasons: first, it is hearsay evidence in that it involves the psychologist in saying what the defendant told her, not by way of complaint but as the truth of what the Crown contends; secondly, that it involves a judgment by the psychologist on the complainant's credibility which is a matter on which the jury alone can express an opinion.”
More recently in R v Gilfoyle , the appellant's pregnant wife was found hanging in their garage. He was convicted of murder because prior to the wife's death, the appellant had asked the wife to write out examples of suicide notes saying that he was doing a suicide project at work as part of the course he was attending on counselling. The appellant was an auxiliary nurse. His wife mentioned this to several friends. The Court of Appeal held that they were admissible to prove his state of mind. On a reference by the Criminal Cases Review Commission, counsel for the appellant sought to adduce evidence of psychological autopsies or posthumous profiling by an eminent psychologist to cast doubt on the deceased's state of mind. The Court of Appeal declined to accept fresh evidence on the grounds, inter alia, that psychological autopsy, like psychological profiling, was not recognised as expert evidence and that English, Canadian and United States cases pointed against the admission of such evidence.
(4) EXPERT WITNESSES AND FOREIGN LAW
(a) Common law
At common law, a person whose knowledge of foreign law was derived solely from study without actual practice might be held incompetent to give evidence. The authority for this proposition is Bristow v Sequeville . In that case, it was necessary to prove the law in force in Cologne . A witness who stated that he was a jurisconsult and adviser to the Prussian Consult in England, had studied law at the University of Leipzig, and knew from his studies that Code Napoleon was in force at Cologne, was not allowed to prove the law of Cologne.
Even at common law this was not a definite rule as opinions of persons legally qualified but not practising in jurisdictions in question and the opinions of bankers on foreign banking laws were admitted as expert evidence on foreign law.
(b) Civil Evidence Act 1972, ss.3 and 4
Section 3 of the Civil Evidence Act 1972 (as amended ) provides:
“3 (1) Subject to any rules of court made in pursuance of … this Act, where a person is called as a witness in any civil proceedings, his opinion on any relevant matter on which he is qualified to give expert evidence shall be admissible in evidence.
(3) In this section “relevant matter” includes an issue in the proceedings in question.”
Section 4 of the Civil Evidence Act 1972 provides:
“(1) It is hereby declared that in civil evidence a person who is suitably qualified on account of his knowledge or experience is competent to give expert evidence as to the law of any country or territory outside the United Kingdom …
(2) Where any question as to the law of any country … outside the United Kingdom … with respect to any matter has been determined … in any [civil] proceedings …
(a) any findings made or decision given on that question in the first-mentioned proceedings shall, if reported or recorded in citable form, be admissible in evidence for the purpose of proving the law of that country … with respect to that matter; and
(c) if that finding or decision, as so reported or recorded, is adduced for the purpose, the law of that country … with respect to that matter shall be taken to be in accordance with the finding or decision unless the contrary is proved.”
Section 3 (1) of the Civil Evidence Act 1972 (CEA 1972) renders admissible expert opinion in civil proceedings and section 4 (1) of the CEA 1972 renders admissible opinions of experts on foreign law who are persons “suitably qualified on account of [their] knowledge or experience.” This is a retreat from Bristow v Sequeville and an enactment of the position in cases sequel to it.
Section 4 (2) (a) of the CEA 1972 allows earlier judicial findings on foreign law made in civil proceedings to be adduced in evidence in subsequent proceedings and accepted as proofs of the findings until the contrary is proved (section 4 (2) (b)).
(5) NON-EXPERT OPINION
At common law, a lay or non-expert witness may state his opinion or impression on questions of identification, condition, comparison or resemblance of persons or things, although he has no special knowledge, skill or experience on such matters. Non-expert opinions have been admitted to prove the publication of a libellous pamphlet and to prove that the damaged window, on a charge of malicious damage, was worth more than five pounds. On a charge of drunken driving, a non-medical witness was allowed to testify that he formed an impression that the accused had been drinking because his eyes were glazed and he spoke with a blurred voice.
The common law position adumbrated above is preserved in section 3 (2) of the CEA 1972 which provides:
“(2) It is hereby declared that where a person is called as a witness in any civil proceedings, a statement of opinion by him on any relevant matter on which he is not qualified to give expert evidence, if made as a way of conveying relevant facts personally perceived by him, is admissible as evidence of what he perceived.”
See C. Tapper (ed.), Cross and Tapper On Evidence ( London : LexisNexis, 2004), at 558.
(1782) 3 Doug 157.
 QB 834.
Ibid., at 841.
 AC 85,  3 All ER 662, PC.
Supra n.1, at 517.
R v Silverlock  2 QB 766.
Sidaway v Bethlem Royal Hospital Governors  1 All ER 643 and Bolitho v City and Hackney Health Authority  All ER 771, HL.
R v Robb (1991) 93 Cr App R 161.
R v Dallagher (2002) The Times, 21 August.
R v Cooke  Crim LR 39, R v Adams  2 Cr App R 467 and R v Doheny  1 Cr App R 369.
R v Clarke  2 Cr App R 45. Cf. R v H , unreported, December 1998 (Bristol Crown Court) and G v DPP  2 All ER 755.
R v Chard (1971) 56 Cr App R 268 where medical evidence concerning the intention at the material time of someone charged with murder was excluded.
See A. Campbell-Tiech, “Lip reading as expert evidence”  5 Arch News 5.
R v Stagg  9 Arch News 4.
R v Gilfoyle  2 Cr App R 57
1953 SC 34.
Ibid., at 40.
 2 QB 766.
Ibid., at 771.
 QB 834 at 841.
CPR, Parts 26-29 and 35.
National Justice Compania Naviera SA v Prudential Assurance Co. Ltd. (Ikarian Reefer) (1993) The Times, 5 March,  2 LL R 68 at 81-82 cited with approval by Otton LJ in Stanton v Callaghan  2 WLR 745 at 774..
Whitehouse v Jordan  1 WLR 246 at 256, per Lord Wilberforce.
Polivitte Ltd. v Commercial Union Assurance Co. Plc  1 LL R 379 at 386, per Garland J and Re J  FCR 193, per Cazalet J.
Derby & Co. Ltd. v Weldon and others (1990) The Times, 9 November, per Staughton LJ.
 All ER (D) 437 (Jul.) (Approved Judgment, QBD summarised by Lexis Nexis UK editors).
Ibid., para. 34.
R v Fitzpatrick (Gerald) (1999) The Times, 19 February, CA.
R v Jennion  1 WLR 317.
 1 QB 159, DC.
 AC 699, HL.
Homicide Act 1957; s.2 (2). See also R v Dunbar  2 All ER 737 and R v Martin (Anthony)  2 WLR 1,  1 Cr App R 323.
R v Silcott, Braithwaite and Raghip (1991) The Times, 9 December, CA.
 AC 705, HL.
 Crim LR 122 at 123, CA. In that provocation case, the Court of Appeal refused leave to call psychiatric evidence that the past physical abuse of the profoundly deaf accused by his father contributed to his loss of self-control.
[1986 Crim LR 395.
Supra n.36. See also R v O'Brien (2000) The Times, 16 February, CA.
 Crim LR 627. See also R v Stockwell (1993) The Times, 11 March, CA where in their Lordships' view a facial mapping expert called to give evidence should have been allowed to do so.
See CPR, r. 32.1 and 32.1.2.
See Liverpool Roman Catholic Archdiocese Trustees Incorporated v Goldberg (No. 2)  4 All ER 950, Ch D where Evans-Lombe J excluded the friend of a party as an expert witness.
See section 118 (1), para. 8 of the CJA 2003.
See section 126 of the CJA 2003.
(1990) The Times, 8 November, CA.
 1 NZLR 362.
 2 Cr App R 57, CA discussed in D. Ormerod, “Psychological Autopsies: Legal Applications and Admissibility”  5 E&P 1.
(1850) 19 LR Ex 298.
Wilson v Wilson [ P 157, Brailey v Rhodesia Consolidated Ltd.  2 Ch 95 and Barford v Barford  P 140.
De Beéche v South American Stores, Etc., Ltd.  AC 148, HL and Ajami v Comptroller of Customs  1 WLR 1405, PC.
By the Civil Evidence Act 1995, s.15 (2), Sched. 2.
Group Torras SA v Sheik Fahad Mohammed Al Sabah & Ors. (1999) The Independent, 25 February, CA.
Fryer v Gathercole (1849) 13 Jur 542.
R v Beckett (1913) 8 Cr App R 204.
R v Davies  3 All ER 97.