In Kennedy v Cordia (Services) LLP [2016] UKSC 6, the Supreme Court had to consider a Scottish appeal arising out of a personal injury claim made by a home carer against her employer Cordia (Services) LLP following an injury to her wrist when she slipped on a snow covered footpath on the way to a home visit. An issue arose as to whether a witness who gave evidence about health and safety requirements, risk assessments and the availability  of  ‘add-ons’ (material that employers could provide to employees to add to their footwear to help prevent slips) was an expert witness.

The Supreme Court set out four general matters which fell to be addressed in the use of expert evidence in civil cases: (i) the admissibility of such evidence (ii) the responsibility of a party’s legal team to make sure the expert keeps to his or her role of giving the court useful information (iii) the court’s policing of the performance of the expert’s duties and (iv) economy in litigation.

The question of admissibility was held to turn on four considerations: (i) whether the proposed expert evidence would assist the court in its task; (ii)   whether   the   witness   has   the   necessary knowledge and experience; (iii) whether the witness is impartial in his or her presentation and assessment of the evidence; and (iv) whether there is a reliable body of knowledge or experience to underpin the expert’s evidence.

Despite being a Scottish case about employers’ liability, this appeal is of use more generally across the UK as a guide to expert witness evidence in civil proceedings (including, of course, COP cases and adult incapacity cases) and contains a helpful review of case law relevant to the four considerations on admissibility. One quote stands out as particularly apt when considering expert reports on capacity: “As with judicial or other opinions, what carries weight is the reasoning, not the conclusion” (Lord Prosser in Dingley v Chief Constable, Strathclyde Police 1998 SC 548, 604).