[2025] UKUT 365 (AAC)

As to causation, the parties are agreed that the accident needs to be “an effective cause” of the injury. This is the term used in regulation 11 of the 1982 Regulations to refer to other possible causes that may need to be considered and is the phraseology adopted in the case law to refer also to the nature of the causal link required between the accident and the injury: see Social Security Legislation 2024/25 Edn, Vol 1: Non Means Tested Benefits at 1.346-347. Where there are multiple contributory causes, the general effect of regulation 11 is, as noted, that the extent of disablement from the accident must be separated from disablement caused by other causes. The standard of proof is the balance of probabilities and, as seems to me to be apparent from the terms of regulation 11, “an effective cause” is a cause that makes a material contribution to the injury, or to the degree of disablement resulting from it. In other words, it is a “but for” test, but a “but for” test that must be applied with care, since the question is not just whether “but for” the accident the injury would have been suffered, but also whether “but for” the accident the injury would have caused the same degree of disablement.

Where the injury is caused by a series of accidents, it is not necessary to be able to identify the time or place of the particular accident or accidents that produced the injury, or to be able to identify the specific influence of each individual accident on the resulting injury, provided that the accidents are, as a series, established to be an effective cause: cf Burrell v Selvage [1921] 1 KB 355, CA at 363-365. (In that case, a worker sustained tiny scratches to her hands in the course of about five months employment in a copper-plating department which led to blood poisoning and arthritis; the Court of Appeal held that the multiple tiny scratches constituted a series of accidents even though it was not possible to date any one such accident.)