## Facts

- Doris Cooke was assured by the Greasley family that she could remain in their property for life; this assurance was not formalized in writing.
- Relying on this assurance, Cooke cared for the family and maintained the property for years.
- Her actions included unpaid labor and personal sacrifice.
- There was a dispute regarding whether Cooke was entitled to remain in the property based on the assurances given by the Greasley family.
- The case addressed the effect of informal property arrangements and the consequences when one party acts on a promise to their detriment.

## Issues

1. Whether the claimant must explicitly prove reliance on an assurance for proprietary estoppel, or whether reliance can be presumed when detriment is shown.
2. Whether Cooke’s actions constituted sufficient detriment to trigger a presumption of reliance.
3. Where the burden of proof lies once detriment has been established in proprietary estoppel claims.

## Decision

- The Court of Appeal held that once a claimant shows detriment arising from reliance on a representation or assurance, a presumption of reliance arises.
- After this presumption, the burden shifts to the defendant to disprove that reliance.
- The court found that Cooke's years of unpaid labor and personal sacrifice were sufficient to constitute detriment and thus invoke the presumption of reliance.
- The Greasley family, as defendants, failed to meet the burden of disproving reliance.
- The judgment clarified and reinforced the equitable nature of the doctrine of proprietary estoppel in English law.

## Legal Principles

- Proprietary estoppel requires assurance, reliance, and detriment.
- A presumption of reliance arises once detriment is demonstrated; the burden shifts to the defendant to disprove it.
- Equity's concern is to prevent injustice and unconscionable conduct, particularly in informal property arrangements where one party acts in reliance on a non-formalized promise.
- The doctrine's application is limited to clear cases of detriment arising from reliance on an assurance.
- The principle assists courts in upholding fairness where promises have induced action to a party’s disadvantage.

## Conclusion

Greasley v Cooke clarified that in cases of proprietary estoppel, once detriment is established, reliance is presumed and the defendant bears the burden of disproving it; this decision remains influential in ensuring equitable outcomes in disputes over informal property arrangements.

Greasley v Cooke [1980] 3 All ER 710