Commentary has been added to the Children and Property Settlement publications regarding the Harman undertaking:

Information obtained on discovery, subpoena or included within an affidavit cannot be used for a collateral or ulterior purpose unrelated to the proceedings in which that production occurs. This is called an implied or ‘Harman’ undertaking after Harman v Secretary of State for the Home Department [1983] 1 AC 280. It is a substantive legal obligation owed to the party who produces the documents and to the court: Hearne v Street [2008] HCA 36 (6 August 2008) at [107]-[108].