Obiter Dictum

Under the English doctrine of precedent, only the ratio decidendi — the rule or principle that explains the court's decision — binds later courts. Everything else in a judgment, including further reasoning that merely underpins the decision and other statements about the law, is obiter dictum. As Lord Burrows explained in his 2024 Lord Toulson Memorial Lecture at the Supreme Court, that further reasoning, alongside all other statements about the law in a judgment, is mere obiter dicta, and the line between the binding decision and the surrounding obiter can have some flexibility depending on how narrowly or widely the rule explaining the decision is formulated.

Because obiter dicta are not binding, a court is not required to follow them, though observations from senior appellate judges are often treated as highly persuasive and can influence how later courts approach a point of law. The Supreme Court's judgment in Dallah v Pakistan illustrates the distinction in practice: the Government of Pakistan's own submissions treated (obiter) observations made by a judge in earlier Pakistani proceedings as not binding on it, since those remarks fell outside what that earlier case actually had to decide.