The Search for Finality in Litigation: Test Claimants in the Franked Investment Income Group Litigation v Commissioners of Inland Revenue [2020] UKSC 47

The decision of the Supreme Court in Test Claimants in the Franked Investment Income Group Litigation v Commissioners for Her Majesty's Revenue and Customs [2020] UKSC 47 reaffirmed that s.32(1)(c) of the Limitation Act 1980 dictates that the commencement of the limitation period of restitutionary claims based on mistakes of law is postponed until the relevant mistake could be discovered by the claimant. However, a new test for ascertaining when such mistakes are rendered discoverable was articulated based on the claimant's ability to recognise that she has a worthwhile claim. Additionally, the Supreme Court ruled that a previously unexamined limitation defence is not precluded by res judicata and abuse ofprocess rules in the context of Group Litigation. This case note provides a summary of the judgment and critically examines its conclusions. It is argued that the new discoverability test is plagued with inherent vagueness and various impracticalities. Moreover, it is claimed that s. 32 (1)(c) does not apply to mistakes of law, since they cannot logically remain undiscoverable. In general, it is argued that the solutions adopted by the Supreme Court do not promote the goals of the principle of finality of litigation.