ABSTRACT
All synallagmatic contracts which involve delivery against instalment payments are subject to a tension between the respective rights of buyer and seller arising out of the seller's obligation to deliver by the contract date. In the field of construction law, one consequence of the prevention principle is that the employer cannot hold the contractor to a specified completion date, if the employer has by act or omission prevented the contractor from completing by that date. The obligations assumed by the parties on entering into such a contract are therefore an amalgamation of those found in both the sale of goods context and non-marine construction. At a stroke and without citation of authority Jackson J applied the prevention principle to cancellation clauses. Further, the absence of any clear authority on this point prior to Multiplex and Adyard is itself suggestive of a general understanding that the prevention principle did not and should not apply to cancellation clauses.
