Court case(1989) 4 SCC 1

The appellants had paid sums to the State under a demand that was later held to be without legal authority. They sued for refund of the amounts as money paid under a mistake of law within s. 72. The State resisted the claim, among other grounds on limitation.

The Supreme Court restated the principle of unjust enrichment as the basis of the claim. Three elements must be present: the defendant has been enriched by the receipt of a benefit; the enrichment is at the expense of the plaintiff; and the retention of the enrichment is unjust. Money paid under a mistake of law is recoverable under s. 72, which draws no distinction between mistake of fact and mistake of law, and for such a claim limitation runs from the date on which the mistake became known to the plaintiff, by force of s. 17(1)(c) of the Limitation Act 1963.