The Court of Appeal for Ontario recently addressed a novel question of appellate jurisdiction: is an order refusing to extend the time to opt out of a class action final or interlocutory? If final, the appeal lies to the Court of Appeal under s. 6(1)(b) of the Courts of Justice Act. If interlocutory, the appeal lies only in the Divisional Court with leave. Justice Lauwers answered this question in Johnson v. Ontario, 2021 ONCA 650: the order is final and appealable as of right in the Court of Appeal.
The final-interlocutory distinction continues to be challenging, particularly in novel areas. Lord Denning M.R. once wrote (before England dropped the distinction) that the “question of ‘final’ or ‘interlocutory’ is so uncertain, that the only thing for practitioners to do is to look up the practice books and see what has been decided on the point” (Salter Rex & Co. v. Ghosh,  2 All E.R. 865 (C.A.)). Where the practice books are silent, as in Johnson, resort must be to first principles.