The parol evidence rule

Abstract

The above is a typical statement of the parol evidence rule. Although the rule can be so simply stated, it has been the source of a great deal of confusion in the law of contract. It was enforced rigidly when it first became established as part of the common law but has since been gradually relaxed. As the courts became faced with new situations where too strict an adherence to the rule would have caused injustice, they created many apparent exceptions to it. The result has been that there are now grave difficulties in the way of stating the true scope of the rule. Sometimes it is suggested that there is no longer any such rule or that it is a "tautology", Wedderburn, "Collateral Contracts" [1959] C.L.J. 58, 60. whereas, on other occasions, the rule has been regarded as still imposing a significant restriction See the excellent article by Lucke, "Contracts in Writing" (1966) 40 A.L.J. 265. At the outset of this inquiry the writer was faced with the daunting task of collecting, and perhaps attempting to reconcile, the multitude of authorities in this branch of the law. However, it soon became apparent that the latter was a fruitless task, such was the maze of conflicting authorities and diverse opinions expressed therein as to the scope of the rule. There has been no leading case which has attempted to collect all these authorities and definitively restate the scope of the rule.