whatever direct use may or may not be made of information given, or material disclosed, under the compulsory process of the court, it must not be overlooked that, quite apart from that, its provision or disclosure may set in train a process which may lead to incrimination or may lead to the discovery of real evidence of an incriminating character The party from whom disclosure is asked is entitled, on established law, to be protected from these consequences.
That point was also made by Gibbs CJ in Sorby v The Commonwealth [5] in words with which I agree:
If a witness is compelled to answer questions which may show that he has committed a crime with which he may be charged, his answers may place him in real and appreciable danger of conviction, notwithstanding that the answers themselves may not be given in evidence. The traditional objection that exists to allowing the executive to compel a man to convict himself out of his own mouth applies even when the words of the witness may not be used as an admission. It is a cardinal principle of our system of justice that the Crown must prove the guilt of an accused person, and the protection which that principle affords to the liberty of the individual will be weakened if power exists to compel a suspected person to confess his guilt It is true that in some cases the legislature may consider that it can only achieve the intended purpose of the statute by limiting or abrogating the privilege against self-incrimination, but, as I have said, if the legislature intends to render the privilege unavailable it must manifest clearly its intention to do so.
And by Mason, Wilson and Dawson JJ in the same case [6] :
the privilege protects the witness not only from incriminating himself directly under a compulsory process, but also from making a disclosure which may lead to incrimination or to the discovery of real evidence of an incriminating character.
1. Sorby v The Commonwealth (1983) 152 CLR 281 at 312, per Murphy J.
2. [1982] AC 380 at 443.
3. (1983) 152 CLR 281 at 294-295.
4. Sorby (1983) 152 CLR 281 at 310. And see also Lord Eldon LC in Paxton v Douglas (1812) 19 Ves Jun 225 at 228 [34 ER 502 at 503].