## Facts

- Mr. Cobbe, a property developer, and Yeoman’s Row Management Ltd (YRML) entered into an oral agreement in principle regarding the redevelopment and sale of a block of flats in London.
- The understanding was that Mr. Cobbe would obtain planning permission for redevelopment, after which YRML would sell him the property for an agreed price, with profits from the development to be split.
- Mr. Cobbe incurred considerable time and expense in obtaining the planning permission.
- Once planning permission was granted, YRML refused to proceed with the sale, arguing that no binding contract was finalized.
- Mr. Cobbe sued, relying on proprietary estoppel, asserting he had relied on YRML’s assurances to his detriment.

## Issues

1. Whether an oral agreement in a commercial context lacking certainty and completeness can support a claim of proprietary estoppel.
2. Whether reliance on such informal assurances, leading to detriment, suffices to establish an estoppel in a commercial negotiation between experienced parties.
3. Whether YRML’s conduct amounted to unconscionable behavior necessary to ground equitable relief.

## Decision

- The House of Lords dismissed Mr. Cobbe’s claim for proprietary estoppel.
- The oral agreement was held to be too vague and incomplete for estoppel to apply; material terms, including profit-sharing, were not sufficiently defined.
- The parties, as experienced businesspeople engaging in commercial negotiations, were expected to formalize their agreement in writing.
- The court found that YRML’s conduct, although described as opportunistic, did not rise to the level of unconscionability required for proprietary estoppel.
- The court reaffirmed that proprietary estoppel is not intended to enforce informal or uncertain agreements in commercial contexts.

## Legal Principles

- Proprietary estoppel in commercial settings requires clear and unequivocal assurances, reliance leading to detriment, and unconscionability, with higher standards of certainty and formality than in domestic arrangements.
- Courts are reluctant to enforce informal or incomplete agreements between sophisticated commercial parties, highlighting the necessity of documented and finalized contracts.
- The distinction between commercial and domestic contexts is essential; the courts adopt a stricter approach in the former, presuming equal bargaining power and access to legal advice.

## Conclusion

The House of Lords held that proprietary estoppel cannot be used to enforce informal, incomplete, or uncertain agreements in commercial negotiations, stressing the importance for parties to clearly document and formalize their arrangements, as informal assurances will not generally found equitable relief in such contexts.

Yeoman's Row Management Ltd v Cobbe [2008] UKHL 55