A lawyer cannot be forced to disclose any information about her/his client, even their identity. This means complete confidentiality. Solicitor-client privilege (a.k.a. lawyer-client privilege) dictates that it is a lawyer’s duty to not disclose communications and information about her/his client without the client’s consent. This Law Society of Ontario article states very well the importance of this privilege [my emphasis]:
[Solicitor-client privilege] is for everyone to feel safe knowing that their discussions with their lawyer are private and cannot be disclosed to anyone without their express permission.
This is the law — and it is one of your constitutional rights and protections.
Solicitor-client privileged communications are out of reach of third parties. No third party, including the police, can make your lawyer disclose these privileged communications to them.
The Supreme Court of Canada stated that solicitor-client privilege is a principal of fundamental justice and recently held that even the Canada Revenue Agency cannot force a lawyer to disclose the identity of her/his clients. That’s correct: a lawyer must guard your identity as a client under solicitor-client privilege from forced disclosure, even from law enforcement and the government. The Law Society of Alberta has taken a strong stance in its guidance to lawyers regarding third party demands for disclosure of a client’s confidential and privileged information:
Privilege belongs to the client, not to the lawyer, and exists whether or not the client asserts a claim of privilege. The decision to claim privilege must be that of the client, not of the lawyer, regardless of the lawyer’s view about the validity of the potential claim.
Solicitor-client privilege is, thus, a lawyer’s professional duty to protect a client’s confidential information and the law in Canada that is zealously guarded by the Courts and the law societies for the client’s benefit.