Fact, future and fiction: Risk and reasonable reliance in estoppel

This paper argues that a common theme underpins the doctrines of estoppel by representation and convention, promissory and proprietary estoppel. In each case, it is the law's concern to respond appropriately to, and not to reward, undue risk-taking on the part of claimants in a non-contractual context. In doctrinal terms, this concern is mediated through the common requirement that the claimant must have acted in reasonable reliance on an assumption induced by the defendant. This paper concludes that the way remains open for the development of a coherent and unified doctrine of reliance-based estoppel moulded around the requirement of reasonable reliance.