The term repudiation is used in different senses.
First, it may refer to conduct which evinces an unwillingness or an inability to render substantial performance of the contract.
This is sometimes described as conduct of a party which evinces an intention no longer to be bound by the contract or to fulfil it only in a manner substantially inconsistent with the party's obligations.
It may be termed renunciation.
The test is whether the conduct of one party is such as to convey to a reasonable person, in the situation of the other party, renunciation either of the contract as a whole or of a fundamental obligation under it.
In this case, we are not concerned with the issues that arise where the alleged repudiation takes the form of asserting an erroneous interpretation of the contract.
Nor are we concerned with questions of inability as distinct from unwillingness.
Secondly, it may refer to any breach of contract which justifies termination by the other party.
It will be necessary to return to the matter of classifying such breaches.
Campbell J said this was the sense in which he would use the word “repudiation” in his reasons.
There may be cases where a failure to perform,
even if not a breach of an essential term (as to which more will be said),
manifests unwillingness or inability to perform
in such circumstances that the other party is entitled to conclude that the contract will not be performed substantially according to its requirements.
This overlapping between renunciation and failure of performance may appear conceptually untidy, but unwillingness or inability to perform a contract often is manifested most clearly by the conduct of a party when the time for performance arrives.
In contractual renunciation, actions may speak louder than words.