Maggs (Trading as BM Builders) v Mark [2006] EWCA Civ. 1058
The general rule in English Law is that where there is a written contract the court should not look at the subsequent conduct of the parties in order to construe the terms. However, where the contract is partly written and partly oral the court may look at subsequent conduct in order to construe the parties’ original intentions. In determining the terms of an oral contract it is necessary to look at the facts of the case and what was said and done subsequent to the agreement may help to determine what the parties’ original intentions were.