The common law has long treated it as unfair to "conscript" or force an accused person to be his own betrayer in a criminal case. As a matter of principle, it is believed that a person should not be required to answer an allegation made against him unless and until the Crown has charged him and established "a case to meet" during trial by presenting evidence supporting the allegation. Until then, he should not have to dignify the allegation with a response. In modern times this notion is "intimately linked to our adversarial system of criminal justice and the presumption of innocence."1It is a vestige of the revulsion that was felt over the ancient courts of Star Chamber, which would detain suspected enemies of the state on mere suspicion, compel them to swear an oath, and then require them on pain of punishment to answer questions asked about what they were thinking or what they believed. The idea that self-incrimination is offensive rests, therefore, on ideas about privacy and the inherent dignity of individuals.2It is also about the abuse of state power and the risk that compelling accused persons to respond can produce unreliable information.3Hence, the principle against self-incrimination supports "limits on the extent to which an accused person can be used
as a source of information about his or her own criminal conduct."4At its heart it is about choice. Individuals should be free to "choose whether to co-operate with the state and, if they choose not to, [they should] be left alone by the state"5unless and until the Crown proves that they have violated a pre-existing rule of law.
In order to vindicate the principle against self-incrimination, the common law developed a number of precise rules, including the privilege against self-incrimination (the right of any witness in any proceeding to refuse to answer questions that may incriminate them), the right of accused persons to decide whether to testify at their own trials, and the rule excluding involuntary confessions. As can be seen, each of these rules is concerned with "testimonial" self-incrimination6- situations where accused persons are made to act like witnesses against themselves by speaking about their own guilt. For more than a hundred years, the principle against self-incrimination provided no protection in cases of non-testimonial conscription - situations where suspects were made to participate in the investigation against them through some physical act such as giving a blood sample,7blowing into a breathalyzer,8or standing in a police line-up.9Confining self-incrimination protection to testimonial compulsion in this way was not arbitrary. It was done in recognition of the fact that whereas compelled statements may well prove to be untrue, the reliability of authentic real evidence is not affected by the manner in which it is obtained. Moreover, forcing testimonial self-incrimination arguably involves a particularly odious breach of privacy as it requires individuals to expose their thoughts and ideas, and "the mind is the individual’s most private sanctum."10Finally, when a person speaks about his guilt, he is creating new, previously unavailable evidence that will assist the Crown, which is not the case when he is required to hand over pre-existing real evidence.
With the advent of the Charter the self-incrimination concept grew. This happened initially in the context of section 24(2) of the Charter. Section 24(2) requires judges to exclude unconstitutionally obtained
evidence if its admission...