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case brief, case summary
Case Brief Law Notes

CASE BRIEF – Hart v. O’Connor

Hart v. O’Connor, [1985] AC 1000, 2 ALL ER 880

case brief, case summary


Thomas Bruce Hart, Appellant

Joseph O’Connor, Respondent


The present case deals with mental incapacity and unconscionability, and whether a contract made with one of the parties being of unsound mind, amounts to a valid contract. Unconscionable contracts are constructed in such a way that they benefit one party while imposing severe, unreasonable, and unjust terms on the other.

Unconscionability is a contract defense used when there is a mix of unjust contract conditions and inadequate negotiating power. A person lacks capacity concerning a subject under English law if, at the material moment, he is unable to make decisions for himself in connection to the matter due to a disability or disruption in the functioning of the mind or brain.

It makes no difference whether the damage or disruption is permanent or temporary. They cannot also be deemed incapable only based on their age or looks, or based on any conclusions made as a consequence of their conduct.

A person is deemed unable to make decisions for himself if he fails to grasp the information important to the decision, retain that knowledge, utilize that information to make the decision, or express his decision, or is deemed unable only based on his ability to retain information relating to a choice for a short length of time; information in this context includes information regarding the highly probable consequences of selecting one way or another or failing to make the decision.

A person of unsound mind is competent to contract under English law, however, the contract can be terminated at his discretion if he can demonstrate to the court that he was incapable of comprehending the contract and the other party was aware of the same.

As a result, under English law, the contract is voidable at his discretion. In every situation, the assumption is in favor of mental stability at first, but the prevalence of it at the moment of contracting is an issue of fact in all cases.

It makes no difference whether the individual was insane before or after the point in time when the contract was signed, except that it is likely to generate a perception of such illness at the time of contract creation.

In situations when a person is typically of unsound mind, the burden of proving that he was of sound mind at the time is on the person who asserts it.

In contrast, in the event when a person is normally in a sound state of mind, the burden of showing that he was in an unsound state of mind falls on the person who disputes the contract’s legality.

Prior Proceedings

The appellant in 1977 entered into an agreement to purchase farmland in New Zealand, which became the issue of a testamentary dispute.

The plaintiff and Joseph O’Connor, the trust estate’s only trustee at the time, were said to have formed the agreement. The trust’s solicitor and members of the testator’s family took the initiative to sell the trust. The trust’s solicitor drafted all of the agreement’s terms, including provisions for property assessment and the appointment of a surveyor.

The trust’s solicitor forwarded the agreement to the appellant’s solicitor for clearance before delivering it to Jack for signature. Unknown to the appellant, Jack was unsound of mind when he signed the agreement.

In May 1980, the respondents, the property’s trustees and successors, filed a motion to dissolve the agreement on the grounds that Jack was of unsound mind when he signed it, which was unjust to him.

The surveyor appointed by the trust’s solicitor evaluated the land at $180,000 on 1 September 1977, but the surveyor appointed by the respondent trustees afterward valued the land at $197,000 on the same day.

Although Jack’s unsoundness of mind was not evident, the trial judge concluded that his unsoundness of mind, together with the irrationality of the contract as a consequence of the parties’ subsequent imbalance of bargaining power, rendered the contract invalid.

However, the judge ruled in favor of the appellant on the grounds that the respondents had committed laches.

law notes


Jack O’Connor sold a farm to Hart. Jack was 83 and of unsound mind, but Hart did not know this and was fair in his negotiations with Jack’s solicitors. Hart occupied and improved the land.

When one of the Jack’s brothers (Joseph O’Connor, the respondent) took over as trustee of the estate he sought to set aside the contract. O’Connor was successful at trial, which Hart appealed.

The Board declared at the completion of the argument that it would suggest Her Majesty that the appeal should be granted for reasons to be provided later.

As per factual findings that are not being disputed, Mr. Jack O’Connor lacked the mental ability to engage into an arrangement, but this was unknown to the appellant. Mr. Jack O’Connor had since passed away, and the respondents were the current trustees of the trust estate.


Is the contract null and invalid due to the unsound mind of Jack O’Connor?

Rule of Law

A contract that is executed in good conscience with no awareness of the other party’s incapacity is not voidable.


The Court of Appeal determined that there was sufficient evidence to sustain the factual conclusion that Jack lacked the required contractual competence.

It affirmed the trial judge’s decision that the plea deal was unfair, and rejected the argument that there must be an overreaching conduct before a deal may be thrown aside on the grounds of unfairness by an incompetent whose inability was unknown.

Finally, the court overturned the trial judge’s conclusion of laches, allowing the appeal. The case was then remanded to the High Court to assess the amount of compensation due to the appellant.

This was asserted on the basis of farmland improvements and a rise in land values induced by overall inflation during the interim period.


No, the contract was not invalid due to the unsound mind of Jack O’Connor, and the decision was in favor of Hart.

The court determined that Jack O’Connor lacked contractual capacity and recognized the notion that a contract entered into by a party of unsound mind – but who seems to be of sound mind – with another party who is unaware of the unsoundness is legal.

Unless the contract is so unjust that it contributes to equitable deception, there is no injustice that can be attributed to the party who had no awareness of the other’s incapacity.

There was no equitable deception in the situation at hand, thus the contract was legal.