Estoppel and waiver

Estoppel is a legal mechanism which prevents a party from departing from a promise or representation they have made to another party where to do so would cause that other party to suffer detriment. The concept embraces notions of fairness and reasonableness, as it is geared towards protecting a person who has relied upon an assumption or representation to either exist, or to come into existence. This is significant given that it provides an avenue for a party to seek relief outside the contract.

Estoppel can create new rights and be used as a cause of action in proceedings. It is also commonly used as a defence in the form of a ‘shield’.

Some ways that an estoppel can arise are as follows:

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Waiver by election involves the unilateral abandonment of a right or claim, and may occur where one party elects between two alternatives and inconsistent rights. Where one of those rights are satisfied, the other becomes no longer available for the party to assert. For waiver in this context to occur, there needs to be unequivocal words or conduct and knowledge of the right that is being waived.

CASE STUDY

McLachlan v Ryan (1987) 4 BCL 155

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