The legislative scheme
16 The LECO Act makes provision for controlled operation applications (s 5), the determination of such an application (s 6), the form of authority (s 8), the duration of an authority (s 9), the variation of an authority (s 10), the cancellation of an authority (s 12), the effect of the authority (s 13) and the lawfulness of controlled activities and ancillary activities (ss 16, 17 and 18). Relevantly, the Act also expressly provides that certain activities cannot be authorised thereunder (s 7).
17 The provisions of the LECO Act of relevance for present purposes were as follows:
" 3. Definitions
authorised operation means a controlled operation for which an authority is in force and, in Parts 3 and 5, includes any operation in the nature of a controlled operation that is authorised by or under the provisions of a corresponding law.
…
controlled activity means an activity that, but for section 16, would be unlawful.
controlled operation means an operation conducted for the purpose of:
(a) obtaining evidence of criminal activity or corrupt conduct, or
(b) arresting any person involved in criminal activity or corrupt conduct, or
(c) frustrating criminal activity or corrupt conduct, or
(d) carrying out an activity that is reasonably necessary to facilitate the achievement of any purpose referred to in paragraph (a), (b) or (c),
being an operation that involves, or may involve, a controlled activity.
…
5(1) A law enforcement officer for a law enforcement agency may apply to the chief executive officer of the agency for authority to conduct a controlled operation on behalf of the agency.
…
5(2A) In any application, whether formal or urgent, the applicant must provide the following particulars:
(a) a plan of the proposed operation,
(b) the nature of the criminal activity or corrupt conduct in respect of which the proposed operation is to be conducted,
(c) the nature of the controlled activity in respect of which an authority is sought,
(d) a statement of whether or not the proposed operation, or any other controlled operation with respect to the same criminal activity or corrupt conduct, has been the subject of an earlier application for an authority or variation of an authority and, if so, whether or not the authority was given or variation granted.
…
6(1) After considering an application for authority to conduct a controlled operation, and any additional information furnished under section 5 (3), the chief executive officer:
(a) may authorise a law enforcement officer for the law enforcement agency concerned to conduct the operation, either unconditionally or subject to conditions, or
(b) may refuse the application.
…
(3) An authority to conduct a controlled operation may not be granted unless the chief executive officer is satisfied as to the following matters:
(a) that there are reasonable grounds to suspect that criminal activity or corrupt conduct has been, is being or is about to be conducted in relation to matters within the administrative responsibility of the agency,
(b) that the nature and extent of the suspected criminal activity or corrupt conduct are such as to justify the conduct of a controlled operation,
(c) that the nature and extent of the proposed controlled activities are appropriate to the suspected criminal activity or corrupt conduct,
(d) that the proposed controlled activities will be capable of being accounted for in sufficient detail to enable the reporting requirements of this Act to be fully complied with.
(4) In considering the matters referred to in subsection (3), the chief executive officer must have regard to the following:
(a) the reliability of any information as to the nature and extent of the suspected criminal activity or corrupt conduct,
(b) the likelihood of success of the proposed controlled operation compared with the likelihood of success of any other law enforcement operation that it would be reasonably practicable to conduct for the same purposes,
(c) the duration of the proposed controlled operation.
…
7(1) An authority to conduct a controlled operation must not be granted in relation to a proposed operation that involves any participant in the operation:
(a) …
(b) engaging in conduct that is likely to seriously endanger the health or safety of that or any other participant, or any other person, or to result in serious loss or damage to property.
…
(3) It is a sufficient defence to criminal or disciplinary proceedings arising from conduct that has been engaged in by the defendant in reliance on an authority that has been cancelled if the defendant satisfies the court or tribunal before which the proceedings are being heard:
(a) that the defendant engaged in the conduct in good faith for the purposes of, and in the course of, a controlled operation for which the authority had been in force, and
(b) that, had the authority been in force when the defendant engaged in the conduct, the conduct would have been lawful by operation of section 16, and
(c) that the defendant was unaware, and could not reasonably be expected to have been aware, that the authority had been cancelled.
13 While it has effect, an authority for a controlled operation:
(a) authorises each law enforcement participant to engage in the controlled activities specified in the authority in respect of the law enforcement participants, and
(b) authorises each civilian participant (if any) to engage in the particular controlled activities (if any) specified in the authority in respect of that participant.
…
16 Despite any other Act or law, an activity that is engaged in by a participant in an authorised operation in the course of, and for the purposes of, the operation is not unlawful, and does not constitute an offence or corrupt conduct, so long as it is authorised by, and is engaged in accordance with, the authority for the operation."
18 Provision is also made in Part 1AB of the Crimes Act 1914 (Cth) (which includes s 15M) for the authorisation of controlled operations for obtaining evidence with respect to Commonwealth offences. Both the LECO Act and Part 1AB contain parallel provisions for the conduct of controlled operations. It was common ground in the present case that no certificate for such an operation under s 14M of the Commonwealth legislation had been obtained. It was also common ground that both Part 1AB and the LECO Act were enacted as a result of the judgment of the High Court in Ridgeway v The Queen [1995] HCA 66; (1995) 184 CLR 19 (Ridgeway). It will be necessary to refer further to this decision later in these reasons. Finally it was also common ground that the protection of s 16 of the LECO Act did not extend to any offence under Commonwealth law.