Ian Paul McLean & Ors v Brett Reginald McLean

The doctrine of mutual wills requires a clear agreement, contractual or akin to contractual, that the wills will remain unaltered. A common intention, expectation, trust or moral obligation is insufficient. The agreement may be implied, but it must be reciprocal and established by clear and satisfactory evidence. An appellate court should approach an evaluative conclusion on primary facts with restraint. The court left open whether proprietary estoppel could, in principle, produce mutual-will consequences. On the facts, however, no binding representation or reliance had been established.

Reginald and Maureen McLean made mirror wills in 2017, leaving their estates to each other and ultimately to their four children equally. After Reginald’s death, Maureen made a 2019 will leaving her estate to Brett, excluding the other three children.

The three excluded children claimed that the 2017 wills were mutual wills, or that Maureen was prevented by proprietary estoppel from departing from them. Recorder Robertson rejected both claims at the Central London County Court on 26 July 2022. The appeal concerned whether the evidence established a binding reciprocal agreement and whether proprietary estoppel could support mutual-will trusts.

1. Appeal dismissed. The Recorder was entitled to find that the 2017 wills were not mutual wills. The evidence showed trust and a common intention to benefit all four children, but did not establish a legally binding reciprocal agreement that neither testator would revoke or alter the wills.
2. The necessary agreement may be express or implied, and need not be strictly contractual. Nevertheless, it must reach a contractual or equivalent level of commitment. The evidence must be clear and satisfactory, or certain and unequivocal, although the civil standard remains the balance of probabilities. Expectation, trust and an honourable engagement are insufficient.
3. The Recorder’s finding was an evaluative conclusion based on primary facts. The appellate court was required to approach it with restraint and could not reconsider the matter afresh merely because another evaluation might have been possible. The finding that Reginald trusted Maureen did not amount to a reciprocal promise. Maureen’s assurance was not matched by a corresponding commitment from Reginald.
4. The proprietary-estoppel claim also failed on the facts. Even assuming that estoppel could in principle produce mutual-will consequences, there was no representation intended to be binding, received as such, or relied upon. The parties’ conduct was founded on mutual trust rather than an intention to create legal obligations.
5. The court considered that the legal possibility of using proprietary estoppel in the mutual-wills context had some plausibility, particularly where statutory formality requirements might otherwise prevent a contract. It deliberately left that question undecided because it could not affect the outcome on the facts.

• Chancery Division on appeal: The appeal from Recorder Robertson’s decision was dismissed.
• Central London County Court: On 26 July 2022, Recorder Robertson held that no legally binding agreement existed that the 2017 wills would remain irrevocable and unaltered, and rejected the proprietary-estoppel claim.