Express law No. 283

18 November 2019

HT v R [2019] HCA 40: High Court finds 'secret' evidence a step too far

High Court rejects 'secret' evidence, but provides useful guidance on the power of courts to make orders for the protection of sensitive information


The High Court has unanimously found that the admission of 'secret' evidence is neither supported by the doctrine of public interest immunity (PII) nor, at least in criminal cases, an appropriate exercise of courts' inherent/implied jurisdiction. In reaching this conclusion, the High Court has emphasised the extensive powers of courts to tailor appropriate orders that modify and/or reduce the requirements of open justice and procedural fairness to the extent necessary to accommodate the public interest in protecting sensitive information.


The appellant, HT, pleaded guilty in the New South Wales District Court to 11 fraud offences.

HT was a registered police informer. Under s 23 of the Crimes (Sentencing Procedure) Act 1999 (NSW), the District Court was required to take into account HT's assistance in sentencing her for the offences. A 'secret' affidavit outlining that assistance, an analysis of its usefulness, and other sensitive criminal intelligence, was admitted into evidence. The Crown Prosecutor had seen the secret affidavit, but HT and her representatives had not. HT's counsel agreed to this course in circumstances in which the only alternative that had been presented by the Crown Solicitor's Office was to receive, and have provided to the Court, a truncated version of the secret affidavit. The sentencing judge sentenced HT to an aggregate 3 1/2 years' imprisonment, allowing a 20% discount on account of HT's assistance.

The Crown appealed to the Court of Criminal Appeal (CCA) on the ground that the sentence was manifestly inadequate. The CCA allowed the appeal. In the course of the appeal, HT sought access to the secret affidavit. The police opposed access on the basis of PII. The CCA upheld the PII claim, but allowed one sentence from the secret affidavit to be provided to HT's representatives. The CCA proceeded to re-sentence HT, increasing the discount on account of HT's assistance to authorities, but also increasing the aggregate sentence.

HT was granted special leave to appeal to the High Court.

High Court

The High Court unanimously found that HT had been denied procedural fairness before the CCA. Kiefel CJ, Bell and Keane JJ (the plurality) explained that the fact that information in the secret affidavit was not adverse to HT was not to the point. HT had no way of knowing whether it detailed all of the assistance that she had provided and the risks she had taken in providing it. Her counsel had no way of checking any instructions she had given about her assistance against what was recorded in the secret affidavit. There was practical injustice: [25], see also Gordon J at [66].

The High Court unanimously rejected the suggestion that PII supported the 'secret' evidence procedure adopted before the District Court and the CCA. The plurality explained (at [33]):

The procedure developed by the common law with respect to claims of public interest immunity in the course of litigation is of narrow compass. It involves balancing competing interests... The documents in question are viewed by the court and treated as confidential only for the purpose of determining the objection to disclosure...

See also Nettle and Edelman JJ at [55] and Gordon J at [72]-[74].

Similarly, the plurality squarely rejected the argument that ss 7 or 8 of the Court Suppression and Non-publication Orders Act 2010 (NSW), or s 130 of the Evidence Act 1995 (NSW), were sources of power upon which a court could deny a party access to evidence admitted in substantive proceedings: [35]-[38], Gordon J agreeing at [74].

Despite the above, the plurality found that there is no doubt that superior courts, including the CCA, have the power in their inherent jurisdiction to make orders to preserve the confidentiality of sensitive information: [42], see also Gordon [83]. The real question is how this power should be exercised, having regard to the requirements of procedural fairness. The plurality reasoned (at [45]):

In cases such as the present it is difficult to accept that orders could not have been tailored to meet the concerns of the Commissioner, for example by providing [HT's] counsel with access to [the secret affidavit] on terms which would have enabled him meaningfully to take instructions and make submissions.

See also Gordon J at [87].

The plurality observed that other available means of accommodating the public interest in protecting the confidentiality of information whilst still affording procedural fairness include: closed court orders; suppression and non-publication orders; orders limiting inspection to a party' lawyers; and the appointment of an independent solicitor who is to report directly to the Court: [45], contra Nettle and Edelman JJ at [56], [58].

The High Court unanimously found that in the circumstances the CCA should have exercised its residual discretion to dismiss the Crown's appeal on sentence: [51], [55], [90].


This decision is of significance to law enforcement, intelligence and security agencies, as well as administrative decision makers dealing with confidential information.

  1. The decision forecloses the use of 'secret' evidence in criminal proceedings and erects a significant, if not insurmountable, barrier for its use in other court proceedings (absent statutory authorisation).
  2. The decision reiterates the well-established effect of PII (that is, denial of access to, and use by, the parties and the court of information the subject of a successful PII claim).
  3. The decision highlights the extensive and flexible powers of superior courts to make orders accommodating the public interest in protecting the confidentiality of information whilst still affording procedural fairness.

Text of the decision is available at:

For further information please contact:

Tristan Lockwood
Senior Lawyer
T 02 9581 7322

Peter Melican
Senior Executive Lawyer
T 02 9581 7404

Kristy Alexander
Team Leader, Law Enforcement
T 02 9581 7640

Irene Sekler
Senior Executive Lawyer
T 02 6253 7155

Andrew Berger
Senior General Counsel
T 02 6253 7405

Tim Begbie
Senior General Counsel
T 02 6253 7521


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