Guest v Guest [2022] UKSC 27
Guest v Guest is the leading modern authority on remedies for proprietary estoppel. It explains why fulfilment of a clear property promise is normally the starting point, while proportionality, timing and justice to the parties and third parties may require a different form of relief.
Facts
Andrew Guest worked on his parents' dairy farm for more than thirty years, starting full time at sixteen. He received modest wages and did not pursue other opportunities because his parents repeatedly led him to expect that he would inherit a substantial part of the farm. The family relationship later broke down. His parents dissolved the farming partnership, required him to leave and changed their wills so that he would receive no interest in the farm. Andrew successfully claimed proprietary estoppel. The trial judge ordered his parents to pay a lump sum representing 50 per cent of the farming business and 40 per cent of the farm's value. That award effectively accelerated an inheritance expected only on the parents' deaths and might require sale of the farm.
Legal Issue
How should the court fashion relief where a clear inheritance assurance induced decades of detrimental reliance but the promised property was not due until the promisors' deaths?
Held
By a majority, the Supreme Court upheld Andrew's entitlement to relief but altered the remedial approach. Lord Briggs held that the aim is neither fulfilment of expectation nor compensation for detriment as such, but preventing or undoing the unconscionability of repudiating an assurance after detrimental reliance. The normal starting assumption is that holding the promisor to the promise is the simplest way to achieve that aim. The court may nevertheless adjust the remedy for practical justice and should use proportionality to detriment as a cross-check where it can sensibly be applied. Immediate payment of the full expected share gave Andrew the promised benefit too early. The parents were therefore offered a choice: grant Andrew a reversionary interest under a trust, taking effect on their deaths, or make an immediate payment reduced to reflect accelerated receipt. Lord Leggatt, dissenting on remedy, favoured protection against reliance loss.
⭐ Legal Principle
A proprietary-estoppel remedy addresses the unconscionability created when a property assurance is repudiated after detrimental reliance. The normal starting point is to hold the promisor to the promise, but the court may adjust the form, amount or timing for practical justice and should check whether the proposed remedy is out of all proportion to the detriment.
Significance
Guest rejects both expectation fulfilment and detriment compensation as automatic measures. Under the majority approach, remedy is flexible but structured: determine whether repudiation is unconscionable, begin with the assumption that enforcing the promise is the simplest response, consider reasons for a different form of relief and use proportionality as a cross-check rather than a mathematical measure. The decision refines Jennings v Rice and sits alongside Thorner v Major. It is particularly important where an expected inheritance is valuable, postponed and difficult to accelerate without disrupting the promisor's continuing ownership.
Common exam questions about this case
Is compensation for measurable financial loss always the remedy in proprietary estoppel?
No. Proprietary estoppel is not confined to reimbursing expenditure or lost wages. Where a clear property promise induced detrimental life choices, holding the promisor to the promise is normally the starting point. Guest treats proportionality as a cross-check rather than a demand to value detriment, and the court may adjust the amount, form or timing where practical justice between the parties and to third parties requires it.
Why was the original immediate lump sum problematic in Guest?
Andrew had expected to receive property only when his parents died. Paying the full value immediately accelerated that benefit and could force a sale while the parents were still living. The majority therefore required the timing advantage to be removed, either through a future reversionary interest or by discounting an immediate payment to reflect early receipt.
What structured approach to remedy emerges from Guest?
The court first asks whether repudiation of the assurance is unconscionable in light of the claimant's detrimental reliance. At the remedial stage it normally starts with the assumption that holding the promisor to the promise is the simplest response. It then considers practical justice, the parties and third parties, timing and any demonstrated disproportionality between the proposed remedy and the detriment. The final award may therefore alter the form, amount or timing of performance.