Section 7 of the Canadian Charter of Rights and Freedoms provides that “everyone has the right to life, liberty and security of the person and the right not to be deprived thereof except in accordance with the principles of fundamental justice.” The right to a fair trial is a principle of fundamental justice and requires the disclosure of the “fruits of the police investigation” as necessary to enable an accused person to make full answer and defend himself or herself against the charges that have been laid. The Crown must disclose all relevant information to the accused, whether inculpatory or exculpatory, subject to the right to refuse to disclose information that is privileged or plainly irrelevant. Prior to the Charter the Crown had absolutely no obligation to disclose anything and in practice, a trial was like an ambush.
Department of Justice Canada’s Internet site