In Turnbull v Office of Environment and Heritage [2021] NSWCCA 190, the NSW Court of Criminal Appeal ("CCA") dismissed an attempt by a defendant to significantly expand the application of the 'accusatorial principle' (the "Principle")—which has traditionally required the prosecution to prove its case without any compelled assistance from the accused.

Certain regulatory authorities in Australia can bring civil and criminal actions against persons who breach legislation. One such authority in New South Wales is the Office of Environment and Heritage ("OEH"). 

The OEH brought a civil action against Grant Turnbull for clearing land in breach of the Native Vegetation Act 2003 (NSW), seeking a restraining order and a remediation order from the Land and Environment Court ("LEC"). In that action, Turnbull voluntarily admitted to a breach of the Act. At that time, there was no indication that the OEH was planning to bring criminal proceedings. Before delivery of the judgment, the OEH brought criminal proceedings in the LEC for the same breach. Turnbull sought to exclude that admission in the criminal proceeding based on the Principle. 

Turnbull argued that the Principle extended to exclude evidence in a criminal trial that had been broadly 'elicited', rather than strictly 'compelled' under the threat of sanction, by a regulatory authority in earlier civil proceedings. Turnbull emphasised this was especially true where the authority in earlier proceedings was the prosecutor in the subsequent trial. The LEC rejected that claim in the first instance.

On appeal, the CCA determined that, although compulsion in the strict sense (i.e., under the threat of sanction) is not an essential element of the Principle, it could not be used to exclude in criminal proceedings statements which were voluntarily provided in an earlier concluded civil proceeding. However, the CCA indicated that the Principle could substantiate a motion to temporarily adjourn civil proceedings where there was a concurrent criminal trial with a shared subject matter. 

This judgment highlights the need for defendants in civil proceedings where there is a possibility of future criminal proceedings on the same facts to consider not making any admissions which can be used in later criminal proceedings.