Where a contractual power is designed as an enduring obligation, with features contemplating long-term performance and the possibility of changed circumstances, the court will not readily imply a term requiring exercise within a reasonable time from the date of the contract. The implication of a reasonable time depends on the particular instrument and its context, not on generalised propositions. If a reasonable time is implied, it runs from the triggering event, not from the date of the contract. Generalisations in textbooks and other cases about implication of reasonable time requirements are empirical observations, not propositions of law.
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