Piepkorn, An application by

This matter concerned an application by Piepkorn for leave to appeal to the High Court of Australia against a decision of the Full Federal Court. The dispute arose from a challenge to the validity of a notice of assessment issued by the Commissioner of Taxation. Piepkorn sought to argue that the notice was invalid due to alleged procedural irregularities in its issuance.

The primary legal issue before the High Court was whether the Full Federal Court had erred in its interpretation and application of the relevant provisions of the *Taxation Administration Act 1953* (Cth) concerning the validity of tax assessments. Specifically, the court was required to consider the consequences of any alleged procedural defects in the issuing of a notice of assessment and whether such defects rendered the assessment void *ab initio* or merely voidable.

Crennan J, in considering the application for leave to appeal, focused on the established principles of administrative law regarding the validity of official acts. His Honour noted that for an assessment to be considered void, the defect must be so fundamental as to go to the root of the power exercised, rendering the act a nullity. Mere procedural irregularities, while potentially grounds for review or appeal, typically do not vitiate the entire assessment unless expressly provided for by statute or if they result in a substantial denial of natural justice. The High Court ultimately determined that the Full Federal Court's decision did not disclose an arguable error of law warranting the grant of leave to appeal.

Leave to appeal was therefore refused.