Barton v Armstrong – Case Summary

Barton v Armstrong

Privy Council (Australia)

Citations: [1975] 2 WLR 1050; [1976] AC 104.


The parties were shareholders in a company. The appellant alleged that he had been coerced into agreeing to buy out the respondent’s interest in the company. He alleged that the respondent had threatened to have him murdered. The trial judge found that the respondent had made these threats. However, he also found that the appellants true motivation for making the agreement was commercial necessity, rather than because he was threatened. The appellant appealed.

  1. Did the appellant need to show that the threats caused the contract to establish that the contract was void for duress?

The Privy Council allowed the appeal. The appellant was not required to show that he would not have entered the contract had the threats not been made. It was sufficient that the threat operated on his mind or ‘contributed’ to his decision. This was the case on these facts, so the contract was void.

This Case is Authority For…

Where a claimant shows that the defendant exercised duress through the threat of violence, there is no need to show that they would not have made the contract had the threat not been made. Rather, the burden is on the defendant to show that the threat did not contribute at all to the decision. It does not matter that the claimant had other reasons or motives which might have led them to make the same decision.


Lord Wilberforce and Lord Simon dissented. They accepted that the threats only needed to be ‘a’ reason to enter the contract, not the only reason or the most important reason. However, they thought that on the facts that it was not established that the threats contributed to the decision. They characterised the decision as entirely motivated by commercial necessity.