Highdawn Pty Ltd v John Howard

Highdawn Pty Ltd and John Howard were parties to a dispute concerning the interpretation and enforceability of a deed of settlement. The matter came before Heath Wilson in the Supreme Court of New South Wales.

The central legal issue before the Court was whether the deed of settlement, which contained a release of certain claims, was valid and enforceable, or whether it was vitiated by a fundamental mistake. Specifically, the Court had to determine if the parties, at the time of entering into the deed, shared a common assumption about a crucial fact, and if the falsity of that assumption rendered the performance of the contract impossible or radically different from what was contemplated.

Justice Wilson found that the parties had indeed entered into the deed of settlement under a shared, but mistaken, assumption regarding the existence of a particular debt. This mistake was fundamental to the agreement, as it underpinned the entire basis upon which the settlement was reached and the release was granted. Applying the principles of common mistake, the Court held that the deed was void *ab initio* because the mistake was so fundamental that it rendered the contract impossible to perform in the manner intended by the parties. The Court reasoned that the release, which was the core of the deed, was predicated on a factual basis that did not exist, thereby frustrating the very purpose of the agreement.

Consequently, the Court declared the deed of settlement void and ordered that it be set aside.