BODY * 7 exception to the parol evidence rule: 1. Exception is that custom or trade usage were allowed by court and it is part of the contract although it is not included in express terms “to annex incidents to written contracts in matters with respect to which they are silent”. This applies in commercial transaction.
Case: Hutton v Warren 2. Exception was about the delay operation contract made by an oral agreement to wait until an event occurs or known as condition precedent, where it was a condition that usually included in the contract to be fulfilled before the contract becomes operative.
Case: Pym v Campbell 3. Exception was to confirm that the contract was not the whole contract.
Case: Van den Esschert v Chappell 4. Exception was when the language of the written contract was ambiguous, that made the agreement looked incomplete of explanation
Case: Rankin v Scott Fell & Co (1904) 5. Exception was when there was an obvious mistake in the contract, then the court may fix the contract in certain situations because the terms of the written contract may not actually stated what the parties have been resolved.