• In the case of Barton v Armstrong [1976] AC 104, physical duress can be established when a threat is held to be a cause of the threatened party to enter into a contract. The threat does not need to be the primary, only, or “but for” cause, it needs only to be established as potential cause that contributed to the signing of the contract, even if there is a possibility that the threatened party would have entered the contract anyway.

Facts of the Case

  • D and C were the major shareholders in a company.
  • C entered into an agreement by deed in which he agreed to buy D’s interest in the company.
  • C later alleged that D had coerced him into entering the deed by using death threats and therefore exerting unlawful pressure on C. C sought to make the agreement void as a result.
  • The trial judge found that D had threatened C, but that duress was not the primary reason why C entered the agreement. It was established that because commercial necessity was the predominant reason for entering the agreement, the threats did not cause or coerce C to enter it. The case was dismissed.
  • The Court of Appeal held this decision, stating that the agreement would only void if C established that but for the threats, he would not have signed the agreement. The court held that C had failed to establish this and dismissed the appeal. C then appealed this decision.

Issues in Barton v Armstrong [1976] AC 104

  • Does physical duress have to be established as the predominant or primary reason for a party to enter a contract in order to make the contract void?

Held by Privy Council

  • Appeal allowed.

Lord Cross

  • There is no onus on C to establish that the threats were the but for cause for entering into the agreement. It was for D to establish that the threats and the pressure that he was exerting on C did not contribute to C’s decision to sign at all. D had to prove that there was no possibility whatsoever for the threats to be a cause.
  • C is established to have been in genuine fear for his life and in real mental torment directly as a result of the threats made by D and the circumstances surrounding them. It is reasonable to believe that C thought that the threats would cease upon signing the agreement.
  • Whilst C may have signed the documents even if D had not threatened him, it is reasonable to infer that the threats and unlawful pressure in fact contributed to his decision to sign the documents.
  • “It would be unrealistic to hold that [the threats] played no part in making Barton decide to execute the documents.”
  • Appeal allowed and a declaration made that the deed entered by C was void, as C had entered the agreement under duress.