IANAL but it would seem to me that one party consent just means you can record it. It does not automatically mean you can divulge. And since you agreed to the

IANAL but it would seem to me that one party consent just means you can record it. It does not automatically mean you can divulge. And since you agreed to the chatham rules not to (i.e. you entered into a contract) you can still be liable for breach of contract in a civil court, with potential penalties and damages if those were part of the contract. Of course anything you record can still be used in criminal or civil proceedings (e.g. if your interlocutor admits to a crime or utters illegal or tortuous speech, such as fraud, harassment, or verbal abuse).