The interaction of the law of property and the law of restitution is one of the more difficult issues facing the law today. The dominant theory of restitution1 draws a crucial distinction between claims to vindicate pre-existing and persisting property rights and claims to reverse unjust enrichment.2 While the “passive”3 protection of persisting property rights is the province of property law, the law of restitution is concerned with the creation of rights where none existed before. At the centre of the problematic interaction between property law and restitution law is the ground of restitution known as “ignorance”.4 According to Professors Birks and Burrows, if the plaintiff’s mistake in benefiting the defendant justifies restitution, so a fortiori must the plaintiff’s complete ignorance of the conferral of the benefit. Such ignorance, however, would equally seem to prevent title in property received by the defendant from passing to the defendant, with the result that the plaintiff’s claim would appear to rest on his persisting title.