Hartog v Colin and Shields  3 All ER 566
Contact – Void – Mistake – Acceptance – unilateral mistake
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.
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 The issue in this case was whether the contract would be rescinded for the mistake to the price of hare skin.
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.