ABSTRACT
Undue influence is an equitable concept that supplements the common law vitiating factor of duress. It operates largely through the application of presumptions. In relation to actual undue influence, the claimant must prove, on the balance of probabilities, that in relation to a particular transaction, the defendant used undue influence. The primary remedy for undue influence in cases such as the refusal of the courts to enforce the agreement against the person influenced. Undue influence is an equitable concept, which, if proved, makes a contract voidable. Banks and other creditors will in some circumstances be unable to enforce transactions that have been made as a result of the undue influence of a third party. The concept that a transaction must be to the ‘manifest disadvantage’ of the claimant in order for it to be set aside for some types of undue influence derives from the speech of Lord Scarman in National Westminster Bank plc v Morgan.
