Duress, Undue, Influence and Unconscionable Dealing are grounds on which a contract can be set aside because the claimant was induced to enter into it by means which the law considers unacceptable. Professor Enonchong provides a detailed and rigorous analysis of the circumstances where an otherwise valid transaction can be avoided on each of these grounds.
Duress
Duress is a common law doctrine under which a contract may be avoided where the complainant was induced to enter into it by illegitimate pressure, such as a threat of physical violence, a threat to seize or damage property or economic pressure.
Undue Influence
There are two doctrines of undue influence: the equitable doctrine of undue influence is concerned with lifetime transactions (such as contracts), while the probate doctrine of undue influence is concerned with wills. The equitable doctrine of undue influence deals with cases where one person has acquired influence over another, and the ascendant person abuses that influence to induce the other person to enter into a lifetime transaction. It includes an evidential presumption of undue influence in certain cases. Probate undue influence applies in relation to wills. It allows the court to refuse to admit a will to probate where the testator was induced to sign the will by the exercise of undue influence. Unlike equitable undue influence, probate undue influence does not include an evidential presumption of undue influence.