What is the Equitable Duty of Confidentiality and what are the implications of this?

Martin v. MacDonald says that where a client hires a lawyer, many duties and disabilities immediately attach to the lawyer, and therefore it is necessary to impose at once and automatically very strong presumptions about the lawyer’s receipt and use of information from that client. Those presumptions are hard to rebut. C. The Equitable Duty of Confidentiality

Though a lawyer (like anyone else) may owe duties of confidentiality to non-clients, that is not the ordinary situation. Lawyers daily or hourly receive information which they are not obliged to keep confidential, on behalf of the person giving the information. Whether they are so obliged depends upon where the information comes from, and under what circumstances. One of those circumstances is the relationship between the parties. Usually a lawyer has but one client, and information which the lawyer gathers from non-clients is held for the lawyer’s client alone, not for the informants. As noted in Part B, the presumptions in Martin v. MacDonald apply only to information from the lawyer’s client.

Where someone who is not the client gives the lawyer information and expects the lawyer to hold it in confidence, more analysis is necessary. Martin v. MacDonald is not a rubber stamp to apply to non-client situations. The result in law or equity may be the same, or may differ, but more evidence and more legal analysis is needed to reach the result.