Proprietary Estoppel and Responsibility for Omissions

The ‘acquiescence’ category of proprietary estoppel is a rare example of responsibility for pure omissions in private law. On liberal‐individualistic theories of ownership, the policy considerations against liability for nondoing are exceptionally powerful in the context of rights over land. Nevertheless, I argue that in proprietary estoppel the law is justified in imposing a duty on the right‐holder to alert a stranger when his actions are based on a mistake. Owners of property rights are under what H onoré termed a ‘special duty’ to contribute to the social good of efficient market for land by publicising their rights. This ‘duty to speak’ is however relatively weak and cannot completely suppress considerations against liability for omission. While liability in the acquiescence category can be justified in principle, the current law, in which owners who failed to correct the mistake of the relying party incur similar liability to owners who actively encouraged the other party to rely, is untenable.