Karsales (Harrow) Ltd v Wallis [1956] EWCA Civ 4 is an English contract law case which established the rules of fundamental breach. The court was unanimous in the decision handed down by Denning LJ in replacing the Rule of Strict Construction, which stated that the contract was constructed to do only what it says it will do. Karsales has been controversial because it set precedent which says judges can override contracts and create a "better" contract in equity, even though both parties agreed to the original contract.