Mistake

Mistake is one of the vitiating factors in contract law, alongside misrepresentation, duress, and undue influence. The doctrine addresses circumstances in which one or both parties labour under a misapprehension as to a fundamental aspect of the transaction. English law takes a notably restrictive approach: the courts are reluctant to relieve parties from bargains they have freely entered, even where the contract was concluded under a mistake. The policy rationale is straightforward — certainty and the protection of third-party reliance outweigh individualized justice in most cases.

Mistake is conventionally divided into three categories:

1. Common mistake: both parties share the same mistake about a fundamental state of affairs.
2. Mutual mistake: the parties are at cross-purposes, each labouring under a different misapprehension.
3. Unilateral mistake: one party is mistaken, and the other knows (or ought to know) of the mistake.

Only in narrowly defined circumstances will mistake render a contract void at common law. Even then, relief in equity has been severely curtailed since Great Peace Shipping Ltd v Tsavliris Salvage (International) Ltd [2002] EWCA Civ 1407, which abolished the equitable jurisdiction to rescind for common mistake on terms more generous than the common law.

This note examines the doctrinal framework, the leading cases, and the difficult conceptual distinctions between categories of mistake. It also considers the interaction with misrepresentation and rectification, and the controversial status of documents mistakenly signed (non est factum).

Classical foundations

The law of mistake emerged from the tension between two foundational principles: caveat emptor (let the buyer beware) and the need to preserve genuine consent. The classical law, heavily influenced by nineteenth-century laissez-faire ideology, took a narrow view. Lord Atkin's judgment in Bell v Lever Bros Ltd [1932] AC 161 epitomizes this restrictive stance: a contract is void for common mistake only if the mistake renders performance "essentially and radically different" from what was contracted for.

Equity's intervention

Soames v Spencer (1822) and Cooper v Phibbs (1867) LR 2 HL 149 appeared to establish a parallel equitable jurisdiction, less stringent than the common law test. Courts of equity would rescind contracts on terms — imposing conditions to protect innocent third parties and ensure fairness. This dualist regime persisted for much of the twentieth century.

The fusion question

By the late twentieth century, the relationship between common law and equity was unclear. Did equity supplement the common law (offering more generous relief), or did the two regimes simply operate in different fields? Lord Denning MR sought to expand equitable relief in Solle v Butcher [1950] 1 KB 671, holding that equity could rescind on terms even where the mistake did not render the contract void at law. This approach generated doctrinal confusion and inconsistency.

The Great Peace revolution

In 2002, the Court of Appeal in Great Peace rejected Solle v Butcher outright. The court held that there is no separate equitable jurisdiction to rescind for common mistake; the only question is whether the contract is void at common law under the stringent Bell v Lever Bros test. This represents a significant narrowing of relief and a reassertion of contractual certainty over fairness.

(a) The restrictive approach

English law is notably hostile to mistake-based relief. The courts emphasize:

• Sanctity of contract: parties are bound by their agreements, even if their expectations are disappointed.
• Allocation of risk: the contract may implicitly or expressly allocate the risk of a particular contingency to one party.
• Protection of third parties: declaring a contract void ab initio may defeat the rights of bona fide purchasers for value.

As Lord Phillips MR observed in Great Peace at [76], "the common law has not developed a doctrine of mistake that enables a contract to be avoided whenever it would be fair and reasonable to do so."

(b) Void versus voidable

Mistake at common law renders a contract void ab initio if the test is satisfied. The contract is treated as never having existed. By contrast, misrepresentation and some forms of equitable mistake (prior to Great Peace) made a contract voidable, giving the innocent party the option to rescind. The distinction matters for third-party rights: title cannot pass under a void contract, but it can under a voidable one (until rescission).

(c) Categories of mistake

1. Foundation: Explain the test for common mistake established in Bell v Lever Bros Ltd and applied in Great Peace Shipping Ltd v Tsavliris Salvage (International) Ltd. Why is relief so rarely available?

1. Foundation: Distinguish between void and voidable contracts in the context of mistake. Why does the distinction matter for innocent third-party purchasers?

1. Standard: Arthur agrees to buy a painting from Beatrice for £50,000, both believing it to be by Constable. It is later discovered to be a copy worth £500. Beatrice had bought the painting in good faith from a reputable auction house. Advise Arthur.

1. Standard: Clara orders goods online from "Smith & Co Ltd," a reputable company. A fraudster, Dean, has created a fake website using Smith & Co's name and logo. Clara pays Dean, who never delivers. Dean sells Clara's payment details to Ethan, who uses them to buy goods from Fiona. Advise the parties.

1. Challenge: "The decision of the House of Lords in Shogun Finance Ltd v Hudson is unprincipled and produces arbitrary results. The law should treat all contracts procured by fraudulent impersonation as voidable, not void." Discuss.

Essential

• J Cartwright, Misrepresentation, Mistake and Non-Disclosure (5th edn, Sweet & Maxwell 2019) ch 10–15 — the leading monograph; authoritative and up-to-date.

• Treitel / Peel, The Law of Contract (15th edn, Sweet & Maxwell 2020) ch 8 — comprehensive doctrinal analysis.

• McKendrick, Contract Law: Text, Cases, and Materials (10th edn, OUP 2021) ch 16 — excellent case selection and critical commentary.

• Beale (ed), Chitty on Contracts (34th edn, Sweet & Maxwell 2021) ch 6 — the practitioner's bible; detailed treatment of all categories of mistake.

Articles and chapters

• Lord Phillips MR, judgment in Great Peace Shipping Ltd v Tsavliris Salvage (International) Ltd [2002] EWCA Civ 1407, [2003] QB 679 — essential reading; the ratio decidendi overruling Solle v Butcher.

• C MacMillan, 'Rogues, Swindlers and Cheats: The Development of Mistake of Identity in English Contract Law' [2005] CLJ 711 — devastating critique of Shogun Finance.

• P Davies, 'Rectifying the Course of Rectification' [2012] CLJ 71(2) 412 — post-Chartbrook analysis of rectification.

• A Burrows, 'Construction and Rectification' in A Burrows & E Peel (eds), Contract Terms (OUP 2007) — clear exposition of the relationship between interpretation and rectification.

• Dannemann & Vogenauer (eds), The Common European Sales Law in Context (OUP 2013) ch 14 — comparative perspectives.

• Law Commission, Sixth Programme of Law Reform (2022, Item 11) — brief discussion of possible reform of mistake as to identity (no current proposals).