The nine claims in Ministry of Defence v AB,  UKSC 9, related to nuclear tests carried out in the South Pacific by the UK government between 1952 and 1958. The claims were brought in 2004, but the UK Supreme Court has ruled (in a 4-3 decision) that they were out of time.
Applicable limitations legislation starts the running of the clock when there is actual or constructive knowledge that injury is attributable to an act or omission that allegedly constitutes negligence, nuisance or breach of duty. ‘Attributable’ here refers to causation, and to a real possibility of a causal link. Issuing a claim obviously displays the requisite level of knowledge. As does, for the majority of the UKSC, first having a reasonable belief there is a claim – belief that is more then mere suspicion but enough to justify investigation. One can know there is a claim without having the evidence necessary to prove it, but evidentiary obstacles to proving the claim don’t somehow stop the clock. Consulting an expert does not always mean acquiring the requisite knowledge. On the facts, all nine claimants must have had a reasonable belief that their injuries could be attributed to the nuclear tests for longer than the applicable 3-year limitation period, especially in light of their public statements and campaigning on the subject before that time and general public awareness of the health consequences of nuclear fall-out.
The minority tried to differentiate between knowledge and belief, suggesting that while reasonable belief founded on known fact would start the limitation period, subjective belief alone would not. For the minority, because there were no known facts capable of supporting a belief that the injuries were attributable to radiation when the claims were issued, the claims were not time-barred.
[Link available here].