One of the parties could feel aggrieved if evidence on the point were excluded merely because the disputed term was not set out in the written document.
Court of Appeal held that the extrinsic evidence could not be substituted.
The court's decision held that they will stick with the terms of the written agreement.
The parol evidence rule has exceptions to the rule because it may be clear that other terms or agreement have been accepted by both parties but the terms have not been included in the written contract.
This may cause unfairness to the opposite side of the party.
It was first established during the case of Goss v Lord Nugent (1833) and it was concisely stated by Innes J in Mercantile Bank of Sydney v Taylor (1891).
The rule prohibits the parties from amending the meaning of the written document through the use of previous oral declarations that are not stated in the document itself.Rectification is not easily acknowledged and few conditions must be met.Firstly, both parties must come out with a complete agreement that was in writing.Secondly, the written document must contain an error or more.Thirdly, no third party must have acquired an interest in the subject matter of the contract and lastly, the amendment me be capable of expression in clear terms.Before the lease was drawn up, the parties negotiated orally about the payment and decided that the rent could in fact be paid in debts.