In England and Wales the Civil Evidence Act 1972, s 3(1) provides that ‘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'. To be qualified to give expert evidence a witness must demonstrate knowledge or experience of some recognised field of expertise. The influential judgment in Barings plc v Cooper & Lybrand (2001) Lloyd's Rep. Bank. 85 states that this must be ‘a recognised expertise governed by recognised standards and rules of conduct'. On epistemological as well as doctrinal grounds, we endorse this requirement for recognised standards and/or rules as appropriate to most types of expert. It is less appropriate to witnesses whose expertise is based on experience of a particular trade or occupation. So-called ‘trade evidence' has caused particular difficulties in intellectual property cases. We argue that such evidence should be treated as expert opinion evidence, not evidence of fact or lay opinion, and should show some identifiable rigour in arriving at its conclusions, as well as conforming to the standards applicable to all expert witnesses.
Ferguson et al. (Wed,) studied this question.
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