Legal Case Summary
Hartog v Colin and Shields [1939] 3 All ER 566
Contact – Void – Mistake – Acceptance – unilateral mistake
Facts
The defendants, Colin and Shields, were hide merchants that were based in London. The complainant, Hartog, was a furrier from Belgium. The defendants entered into an oral agreement with the complainant to sell him 30,000 Argentinian hare skins and this would be at a price of 10d per skin. However, the defendant made a mistake on their written agreement that said they would sell the complainant 30,000 hare skins at 10d per pound. This would mean that the price difference was one third cheaper for the complainant than had previously been agreed. Hartog accepted this offer, but the defendants refused to fulfil contract.
Issues
The complainant argued he suffered a loss of profit and claimed damages when the defendant did not honour the contract. The defendant argued that Hartog would have known that this was a mistake to the pirce of hare skin and that he had fraudulently accepted the offer. The issue in this case was whether the contract would be rescinded for the mistake to the price of hare skin.
Decision / Outcome
It was held that there was no contract between the complainant and the defendant. Any contract would be void by the mistake of the hare skin price; the complainant would have known that it was normally sold per piece and not by pound. The court said that there is a duty to correct a mistake that is known to not be the real intention of the person making it. You cannot simply take advantage and ‘snap up’ the offer.
Updated 19 March 2026
This summary of Hartog v Colin and Shields [1939] 3 All ER 566 remains legally accurate. The case continues to be good law and is regularly cited in English contract law as a leading authority on unilateral mistake at common law, standing for the principle that a mistaken offer cannot be ‘snapped up’ by a party who knows or ought to know of the offeror’s error. The legal position on unilateral mistake as described in this article has not been materially altered by subsequent statute or case law. Readers should note, however, that the broader law of mistake in contract — including equitable mistake and the effect of mistake on contracts — has been further developed by later cases, most notably Great Peace Shipping Ltd v Tsavliris Salvage (International) Ltd [2002] EWCA Civ 1407, which significantly restricted the equitable doctrine of mistake. That development does not affect the specific common law principle illustrated by this case, but students should be aware that the wider law of mistake is more complex than this single case suggests. The article’s use of ‘void’ to describe the outcome is consistent with the common law analysis applied in the case itself.
