D mistakenly offered to sell P objects at a price per pound per pound when they had meant to offer them at a price per piece and P tried to enforce the mistakenly made offer. Singleton J held that since P must have known that the price was mistaken, he could not insist on the offer.
Singleton J: A party cannot accept and seek to take advantage from an offer which he must have known to be mistaken i.e. a “snapping up” case. The mistake must be “material”.