The concepts and predicates in favour of an enforceable agreement of common interest are essentially similar to those of the common defence agreement. They include sufficient real common interests to justify a derogation from the rules on waiver of solicitor-client privilege. Since the existence of common interests is not as obvious as in the context of the process, it is particularly important that clients and lawyers document the beginning, duration, scope, limits and end of an agreement of common interest. Creation is important to enable the parties to determine precisely when the common interest began in the event of a subsequent dispute. The Court found that both bases were applicable. To explain why the interests of both parties were identical, the court relied on the JDA between RBC and Air Routing, which contracted RBC to participate in Air Routing`s defense of its Texas lawsuit. In addition, the JDA provided a list of non-exhaustive common problems between the parties, including the claimant`s assertion that one or more of the defendants owed the claimant an obligation to validate certain invoices. (One of the allegations made by the claimant against RBC in Ontario was that it owed this obligation, which had been breached.) Here are some tips to increase the likelihood that common defense will protect privilege. In the Tribunal`s view, the corridor communication did not serve the interests justifying the privilege. For example, the communications took place outside the presence of a lawyer (although, as the judge notes, the lawyers were nearby) and were not made for the purpose of obtaining legal advice. The court simply called the communications “a corridor debate [composed of] a JDA member who passed on his independent, non-legal research to another JDA member, while finding that he had sent the same research to his lawyer.”  In addition, the court noted that “the mere fact that the communications took place between co-accused who had adhered to a common defence agreement was no longer sufficient to protect the statements from disclosure.” The conditions, scope and limits of the common defence or public interest privilege may vary considerably from one jurisdiction to another.
State and federal courts differ as to whether they recognize a common defence or public interest privilege and to what extent such a privilege applies. The Colburn case was a class action lawsuit involving allegations of price agreement with respect to credit card fees paid by merchants. Some defendants have reached an agreement and the prosecution continues against the remaining defendants. The defendants announced the existence of a JDA and toll agreements, and the applicant requested a court decision requiring the establishment of all agreements. Common defence relations may exist between civil or co-accused parties and in the civil or criminal context. A common defense may even extend to non-parties such as defendant insurers. Transactions, litigation and commercial disputes often involve several clients with competing interests, but with different lawyers. Often, clients and their lawyers want to communicate with other clients and lawyers without the risk of renouncing existing privileges or immunities. Clients and lawyers can benefit from the options developed by the courts, including common defence or common interest privilege. As a purely legal matter, the common privilege of the defence is an erroneous name, as it is not in fact an affirmative privilege; rather, it is an exception to the waiver rule. In general, the disclosure of inside and confidential information to third parties constitutes a waiver of privilege.
However, those protected by a common defence agreement may avoid renouncing and preserve the privilege, notwithstanding the disclosure of confidential information to third parties. . . .