Canadian Charter of Rights and Freedoms

10. Everyone has the right on arrest or detention
     a) to be informed promptly of the reasons therefor;
     b) to retain and instruct counsel without delay and to be informed of that right;

Section 10(b) of the Canadian Charter of Rights and Freedoms does not mandate the presence of defence counsel throughout a custodial interrogation. In most cases, an initial warning of the right to counsel, coupled with a reasonable opportunity to consult counsel when the detainee invokes the right, satisfies s. 10(b).

The purpose of s. 10(b) is to provide a detainee with an opportunity to obtain legal advice relevant to his legal situation. In the context of a custodial interrogation, chief among the rights that must be understood by the detainee is the right under s. 7 of the Charter to choose whether to cooperate with the police or not (the right to silence).  Normally, this purpose is achieved by a single consultation with counsel at the time of detention or shortly thereafter.

R. v. Sinclair, 2010 SCC 35 (CanLII),
[2010] S.C.J. 35 at para 47 

For there to be such an obligation on police to contact counsel a second time and facilitate a consultation, there must be a change in circumstances such that the choice facing the detained person has been significantly altered.

                                                                                                                                                          R. v. Sinclair, at para. 65
Such an alteration occurs where the adding of an additional criminal charge significantly increases the alleged moral blameworthiness of the accused, and thus the potential penalty the accused faces.

R. v. Moore, 2016 ONCA 964