Law of evidence Essay Example | Topics and Well Written Essays - 1250 words

Law of evidence - Essay Example One example is the case of R v Cannings [2004], where the convictions for the murder of the defendant's sons were quashed on the basis of new medical evidence which discredited the expert witness at trial.2 Although the expert witness (a doctor) was a recognised professional in his field at the time, evidence later showed that his account of what he thought took place was actually fabricated and not backed by the evidence.3 Although the test at the time was passed, the actual quality of the evidence was controversial, so even in this case where the doctor was seemingly an expert at the time, his testimony proved to be damaging at trial. "The better and now more widely accepted view is that so long as a field is sufficiently well-established to pass the ordinary tests of relevance and reliability, then no enhanced test for admissibility should be applied, but the weight of the evidence should be established by the same adversarial forensic techniques applicable elsewhere."4 This test is the current common-law test in order to determine if expert testimony should be submitted. The case involved lip reading evidence being questioned as it is not an exact science or profession; the court held that this passed the test for relevance and reliability which is all that was needed to be allowed. Here, although the validity of the expert evidence was questioned, it proved to be accurate and sufficient. Another case which operated along these lines is that of R v Dallagher (Mark Anthony) [2002], which involved the admission of an ear-print expert who was brought in to analyse and compare an ear-print found at the crime scene with that of the defendant; the court held that although the field is relatively small, the expert was part of a group which were recognised within the field.5 Expected opinion evidence is used in order to assist the court and jury on matters which lie outside the experience or understanding of ordinary jurors or justices.6 If jurors or justices can be expected to understand evidence from their own view on any issue without such expert assistance, then expert testimony is not to be received, as was held in the case of Folkes v Chadd [1782].7 Trials operate on the premise that "courts and juries do not need psychiatrists to tell them how ordinary folk who are not suffering from mental illness are likely to react to the stresses of life."8 The case of R v Henry; R v Manning [1968] held that low IQ is not a mental illness and expert evidence was not admissible to explain behaviour where no mental illness exists.9 Expert evidence will ordinarily be considered necessary and admissible on matters of science, medicine, authenticity or questions of foreign law.10 There are also dangers with expert