Guest v. Guest [2022] UKSC 27

‘One day my son, all this will be yours’ Spoken by a farmer to his son when in his teens and repeated for many years thereafter’. The facts of Guest v Guest [2022] UKSC 27 [1] – inheritance of a family farm - was neatly summarised by Lord Briggs, in a single line.

In reliance of his father’s promise, the son Andrew, for over 30 years, worked on his parents’ farm, earning a very small wage. The parents made wills.  When father and son fall out, the son was removed from the wills.

The son brought a proprietary estoppel claim, seeking enforcement of the promise. The son was successful in making out the claim: it was found that the son had suffered detriment in reliance on his father’s promise, such that it was unconscionable for the promisor (father) from reneging on the promise.

The Supreme Court was required to answer the fundamental question: what is the proper approach to granting relief under the doctrine of proprietary estoppel? Should the remedy be fashioned to fulfil the son’s expectation (as the son argued)? Or should it be limited to compensate him for the ‘detriment’ suffered (as the parents argued)? Put it differently, ‘expectation’ or ‘detriment’?

The majority (represented by Lord Briggs) held that the remedy should be specific enforcement of the promise and the son’s ‘expectation’. The minority argued that the remedy should be compensatory in nature.

The objective of a promissory estoppel remedy, as the majority stressed, is to remedy the ‘unconscionability’ caused by a breach of promise.  The majority also gave the parents a choice between: (1) a non-financial (ie the promised share in the farm held on trust for Andrew until the parents’ death) and (2) financial remedy (a sale of the farm now).

February 2026

Dr. Anthony Lai and Dr. Rita Cheung