In Z v NSW Crime Commission  HCA 7, a man came to a lawyer and sought advice about the implications of anonymously passing to police information about a suspected criminal. The solicitor gave advice, and the client authorised the communication of the information to the police. The solicitor passed it on without advising his client’s identity. Years later, after the suspected criminal allegedly attempted to murder someone, the NSW Crime Commission purported to compel the solicitor to advise the client’s identity and how he could be contacted. The High Court said the solicitor must do so, as did every other judge along the way. The ratio of the decision is that any privilege which did exist over the client’s name and contact details was expressly abrogated by a statute about the Crimes Commission. As to whether there was any privilege in the first place, though, two judges held that the client’s identity was privileged, two held that it was not, and one — the Chief Justice — did not express a view. Update: Deacons’s analysis here.
Earlier decisions bearing on this topic include:
- Commissioner of Taxation v Coombes (1999) 92 FCR 240 at 252 ;
- Hamdan v Minister for Immigration and Multicultural and Indigenous Affairs (2004) 211 ALR 642 at 645-646  per Finn J. The issue was not considered on appeal; cf Minister for Immigration and Multicultural and Indigenous Affairs v Hamdan (2005) 143 FCR 398.
In this case, the NSW Crime Commission investigated the attempted murder. They held a hearing. The governing statute abrogated the right against self-incrimination, and in relation to legal professional privilege, said in relation to such hearings:
‘If: (a) a legal practitioner or other person is required to answer a question …, and
(b) the answer to the question would disclose… a privileged communication passing between a legal practitioner … and a person, the legal practitioner or other person is entitled to refuse to comply with the [Crime Commission’s] requirement [that questions be answered], unless the privilege is waived by a person having authority to do so. However, the legal practitioner must, if so required …, furnish to the Commission the name and address of the person to whom or by whom the communication was made.’
Gleeson CJ with characteristic efficiency, simply held that, obviously, the text which I have italicised in the indented quote abrogated the privilege by clear words, to the extent to which it might otherwise attach to a client’s identity and contact details. In dicta, Hayne and Crennan JJ made comments at  suggesting they agreed, but decided the case on a different basis.
Hayne and Crennan JJ considered that the client’s name and contact details were not privileged in the first place, so that the statute did not arise for consideration. That was because the purpose of the prosepctive client telling the solicitor his name and address was not to seek legal advice: ‘As Lord Esher MR said in Bursill v Tanner (1885) 16 QBD 1 at 4, “The client does not consult the solicitor with a view to obtaining his professional advice as to whether he shall be his solicitor or not.”‘ It was impermissible to look at one conference and say that the purpose of the conference was to seek legal advice on the implications of anonymously passing information to the police and conclude that every communication at that conference was therefore privileged. Each separate communication at the conference must be analysed for a privileged purpose: see . Their Honours dismissed an argument that in the circumstances of this case, the client’s identity was so bound up with what was privileged — the client’s communication of his suspicions — that it should be protected by some derivative privilege. Such an argument could succeed only if it would tend to reveal privileged information, said their Honours, and here, there was no information in respect of which a privilege could be asserted as against the government, once the solicitor had communicated that information to the police: see .
Kirby and Callinan JJ agreed with the Chief Justice’s conclusion that the italicised words expressly abrogated any legal professional privilege attracted to the client’s identity and contact details. But they differed from the conclusion of Hayne and Crennan JJ that there was no privilege over the client’s communication to the solicitor of his identity, expressly taking into account the fear by the solicitor and his client of violence at the hands of the attempted murderer and his associates. They surveyed American cases at :
‘Some of the legal authority in the United States, mentioned by Hayne and Crennan JJ, lends support to that contention. Thus, as Butzner J stated in National Labor Relations Board v Harvey, “[t]he privilege may be recognized when … identification of the client amounts to disclosure of a confidential communication”. For these reasons, in In re Kaplan, the Court of Appeals of New York upheld a claim for privilege where “the client’s name … deserved and needed protection”. Canadian authority referred to by the appellant also lends support to this conclusion. Thus, in Lavallee, Rackel and Heintz v Canada (Attorney General), Veit J in the Alberta Court of Queen’s Bench stated that whilst “some old authorities have held that there is no privilege in a client’s identity … contemporary authorities recognize that, in some situations, it may be critically important”.’