Duress works as a complete common law defence for people who are forced or put under improper pressure to commit a crime. It stops one party from taking advantage of another by becoming involved in unconscionable conduct.
This defence operates in criminal as well as civil law, which mostly applies in contract law.
According to contract law, a lawful agreement can only be reached if both parties enter into it freely and without any pressure. If consent was obtained by improper pressure, the parties will not necessarily be legally bound by a contract. Duress may take the form of illegitimate threats or physical violence in order to pressurize a party into entering a contract.
A party to a contract will not be able to use duress as a defence for legitimate commercial pressure or mere inequality of bargaining powers. However, it is sometimes very difficult to draw a line between legitimate commercial pressure and an improper economic threat. Threats to take business elsewhere, sell to a competitor, or not to give a discount in future, are all likely regarded as legitimate commercial pressure. The nature of the pressure needs to be examined on case by case basis in order to determine whether the pressure is illegitimate.
Illegitimate pressure can be defined as unlawful threats such as a threat to break an agreement or threat to commit a crime.
Duress can be actionable by the innocent party if the following factors are present:
- Compulsion or lack of practical choice for the victim
- The pressure is illegitimate; and
- There was a significant ground inducing the claimant to enter into the contract
The effect of duress makes the contract voidable. A voidable contract is a valid, legally binding contract unless and until it is rescinded or affirmed by the innocent party. It the innocent party chooses to affirm the contract it will be binding and cannot be changed.
When a contract is rescinded, neither party have to perform any future obligations. Duress can also be used as a defence if the other party tries to enforce the agreement or claim damages for breach of it. The innocent party cannot claim damages.


