Duress and undue influence
Duress and undue influence are vitiating factors that make a contract voidable: duress is illegitimate pressure (to the person, to goods, or economic) that leaves the victim no practical choice; undue influence is the improper use of a relationship of trust or ascendancy to procure agreement.
Last reviewed 14 June 2026
Economic duress requires illegitimate pressure (often an unlawful threat) that was a significant cause of the victim entering the contract, with no reasonable practical alternative (The Universe Sentinel; Pao On v Lau Yiu Long).
Undue influence is either actual or presumed; presumed undue influence arises from a relationship of trust and confidence plus a transaction calling for explanation, and can affect third parties such as banks (Royal Bank of Scotland v Etridge (No 2)).
Key cases
- Universe Tankships Inc of Monrovia v ITWF (The Universe Sentinel) [1983] 1 AC 366
- Royal Bank of Scotland plc v Etridge (No 2) [2001] UKHL 44
- Pao On v Lau Yiu Long [1980] AC 614
Frequently asked questions
What is economic duress?
Illegitimate pressure — often an unlawful threat — that is a significant cause of a party entering a contract when they had no reasonable practical alternative. It makes the contract voidable.
What is the difference between duress and undue influence?
Duress is illegitimate pressure or threats; undue influence is the improper exploitation of a relationship of trust or ascendancy. Both can make a contract voidable.