it is called evidence of an implied admission. As long ago as 1796, in R v Crossfield the expression "consciousness of guilt" was used to describe evidence of this kind. In the trial of an alleged conspirator in a plot to assassinate King George III the trial judge directed the jury to the significance of the accused's "flight" from England as "circumstances which do at least infer a consciousness of very great guilt, and if there be no other reason assigned for the conduct of the party, very much corroborating and supporting the charge of the particular guilt that is imputed to him" (emphasis added). In an 1896 American textbook, the learned author wrote that the behaviour of a person who fabricates evidence or lies to conceal facts "necessarily implies an admission of their truth, and a consciousness of their inculpatory effect, if uncontradicted or unexplained" (emphasis added). Both expressions are useful, in the way that jargon is often useful, as a handy tag to refer to this kind of evidence as long as the underlying concept itself is understood and applied correctly. Evidence that a person accused of a crime told a lie about a material fact concerning the crime is a piece of circumstantial evidence. Circumstantial evidence is evidence which proves a fact from which another fact may be inferred. The prosecution leads evidence about the accused's telling of a lie because that fact raises an inference that the accused is guilty of the charged crime. The reason why one might infer guilt is that, people being largely rational, there must have been a reason why the accused told the lie. As was said in Crossfield, "if there be no other reason assigned for the conduct of the party" one might conclude that the circumstantial fact raises an inference of the accused's guilt. This is because a jury can infer that the accused's reason for telling the lie was to hide something that pointed to the accused's guilt and wanting to hide something that points to one's guilt of an offence is the motivation of a guilty person. In that sense, the lie constitutes evidence of "consciousness of guilt" because the lie proves a motivation based on guilt. It can also be regarded as an implied admission of guilt in the sense that it is voluntary conduct by an accused that evinces guilt.
204 His Honour went on to say that there may be competing inferences and there might be a number of non-inculpatory explanations for lies. Furthermore, his Honour made the following observations with respect to the cumulative effect of lies with other lies or with other conduct from which an inference of a consciousness of guilt may be drawn (at [33]):
However, the prosecution’s circumstantial case was not confined to post-offence lies. It included all of the other acts of the appellant to hide Thompson’s killing. Each individual inference of guilt in a circumstantial case need not itself be established beyond a reasonable doubt before a jury is entitled to draw an inference that the appellant was guilty of murder. A jury is entitled to have regard to the whole combination of facts, none of which viewed alone could support that ultimate inference, but which taken together can do so, provided that they reach that conclusion upon the criminal standard of proof. When the lies, which on their own might be equivocal as to guilt, are considered along with all of the other post-offence conduct, as part of an assembly of facts each of which raises its own incriminating inference, then it becomes open to the jury to accept, beyond a reasonable doubt, the ultimate inference that the appellant was guilty of murder.
(Citation omitted; see also Leung v State of Western Australia [2020] WASCA 81 at [38]–[50] per Buss J; R v Hillier [2007] HCA 13; (2007) 228 CLR 618 at [46]–[48] per Gummow, Hayne and Crennan JJ.)
