Kok v Osborne: When Can You Set Aside a Contract for Mistake?

Citation: Kok v Osborne 1993 (4) SA 788 (SE)

The Test for Iustus Error

A contract may be set aside if:

1. Material mistake — About an essential term
2. Reasonable mistake — A reasonable person would have made it
3. Other party knew or should have known — About the mistake

If all three = No consensus = Contract void

Exam Application

Step 1: "Under Kok v Osborne, [party] can set aside the contract for mistake if the mistake was material, reasonable, and the other party knew/should have known."

Step 2: Material? "The mistake about [term] was material because it goes to the root of the agreement."

Step 3: Reasonable? "The mistake was reasonable because [reason]."

Step 4: Other party's knowledge? "[Party] knew/should have known about the mistake because [facts]."

Related

• Sonap Petroleum v Pappadogianis (1992) — Consensus in contract
• George v Fairmead Hotel (1958) — Material vs immaterial mistake

Tags: #contract #mistake #iustuserror #consensus #voidcontract