Procedural scheme governing the laying of criminal charges and the arrest
 Part XVI of the Criminal Code sets out a detailed procedural scheme governing the laying of criminal charges and the arrest, detention and release of persons charged with criminal offences. Among other purposes, Part XVI seeks to minimize, to the extent consistent with the public interest, the pre-trial incarceration of persons charged with criminal offences. To achieve that goal, several provisions of Part XVI permit a peace officer to release an individual, thereby avoiding the need to hold that person in custody pending appearance before a judicial officer: see Criminal Code, ss. 496, 498, 499, 503(2).
 A peace officer who arrests an accused may release that person on a promise to appear. That document compels the named person to appear in court on a specified date in answer to the charge set out in the promise to appear: Criminal Code, s. 501. Failure to appear as required is a criminal offence: Criminal Code, s. 145(5).
 If an accused is released on a promise to appear, two steps are necessary to bring the criminal charges before the court. First, an information alleging the offence(s) must be laid before a justice “as soon as practicable” and “in any event before the time stated in the … promise to appear”: Criminal Code, s. 505. Failure to lay the information “as soon as practicable” renders the promise to appear ineffective and provides a defence to a charge of failure to appear as directed by the promise to appear: R. v. Naylor (1978), 42 C.C.C. (2d) 12 (Ont. C.A.), at p. 19; R. v. Gougeon reflex, (1980), 55 C.C.C. (2d) 218 (Ont. C.A.), at pp. 230-31, leave to appeal to S.C.C. refused 35 N.R. 83n; R. v. Markovic 2005 CanLII 36251 (ON CA), (2005), 77 O.R. (3d) 752 (C.A.), at paras. 23-25, leave to appeal to S.C.C. refused,  S.C.C.A. No. 530.
 The second step necessary to move the criminal charges forward also takes place when the information is laid before the justice of the peace. The justice of the peace must decide whether to confirm or cancel the promise to appear. If he or she cancels the promise to appear, it is of no force and effect, the accused is not required to appear at the time and place set out in the promise to appear, and failure to appear is not a criminal offence. A justice of the peace may cancel a promise to appear for various reasons. For example, the justice of the peace may conclude that the criminal charge(s) should not have been brought against the accused, or that some other process should be used to compel the attendance of the accused: Criminal Code, s. 508.
 Although the promise to appear and other similar mechanisms for release by the police introduced into the Criminal Code by the Bail Reform Act, S.C. 1970-72 c. 37, gave the police broad powers of release, those powers were deficient in that they did not permit the police to impose conditions as a term of the release. Unless the police were satisfied that the arrested person should be released without any conditions, they had to detain that person pending appearance before a justice of the peace. The justice of the peace could then release that individual on the appropriate bail conditions. This shortcoming was eventually cured by amendments that gave a peace officer who released the person on a promise to appear, the power to require that person to enter into an undertaking before being released: Criminal Code, s. 503(2). That undertaking could contain one or more of the conditions set out in s. 503(2.1) of the Criminal Code and is aptly described as “police bail”: see Gary T. Trotter, The Law of Bail in Canada, 2nd ed. (Scarborough, ON: Carswell, 1999), at pp. 94-100.
Reference: R. v. Oliveira, 2009 ONCA 219 (CanLII), <http://canlii.ca/t/22qlw>