Introduction
Non est factum, Latin for "it is not my deed," is a restricted defense in contract law. It allows a person who signs a document to avoid liability by showing a serious error about the document’s core purpose or type. The defense applies only in exceptional cases, protecting signers from deceit while upholding trust in written agreements. A successful non est factum claim makes the contract invalid from the start, as if it was never created. Specific conditions must be met to use this defense, requiring careful examination of the facts tied to the signing.
The Nature of the Misunderstanding
The mistake required for non est factum must relate to the document’s core purpose, not just its details. A wrong view about legal effects, without misunderstanding the document’s basic type, will not work. For example, thinking a loan agreement records a gift shows a serious error; misreading the interest rate does not. The signer must misunderstand the fundamental nature of what they signed. Lord Reid’s analysis in Gallie v Lee [1971] AC 1004 separates a document’s core purpose from its exact terms.
The Role of Carelessness
A signer does not have to show complete carefulness, but serious neglect may prevent a non est factum claim. Expected care depends on the situation. A blind or uneducated person, for instance, needs more help than someone who can read. However, even a literate person might avoid liability for some neglect if tricked. The House of Lords in Saunders v Anglia Building Society accepted this, stating that even careful individuals can be misled by deliberate deceit.
Establishing the Defense: Burden of Proof
The person claiming non est factum must prove two points: a serious error about the document’s purpose and that their level of neglect was not unreasonable. Evidence might include the signer’s explanation, witness statements, or expert analysis of the document. Courts consider all factors, such as the signer’s potential loss, the type of false claims made, and the document’s complexity. Proving both the error and sufficient care is needed for the defense to succeed.
Non Est Factum and Vulnerable Individuals
This defense is especially important for protecting older adults or those with limited mental capacity. Such individuals are more likely to be pressured into signing documents they do not understand. Cases involving these groups require courts to balance protection with the need for dependable contracts. Lloyds Bank Ltd v Bundy [1975] QB 326 addresses unfair pressure in contract disputes.
Distinguishing Non Est Factum from Other Doctrines
Non est factum differs from misrepresentation (false claims leading to a contract) and undue influence (forced signing). While these areas may overlap, non est factum directly applies when the signer misunderstood the document’s core purpose, making it invalid immediately. Barton v Armstrong [1976] AC 104 examines how threats affect contract validity.
Conclusion
Non est factum is a notable but narrow defense in contract law. It helps those who sign documents without understanding their core purpose. To succeed, a signer must show both a serious error and acceptable care. The ruling in Saunders v Anglia Building Society and later cases shape how courts use this defense. Knowing its specific use, especially for vulnerable groups, is essential for legal professionals and those creating agreements. This defense supports true victims of deceit while upholding trust in written contracts. Courts continue to refine its application, balancing signer protection with the need for dependable agreements. Further study of cases like Petelin v Cullen (1975) 132 CLR 355 can broaden understanding of this defense’s details.
