The rule originated in June, 1927, at what is now best known as Chatham House (formally known as the Royal Institute of International Affairs) with the aim of guaranteeing anonymity to those speaking within its walls in order that better international relations could be achieved. It is now used throughout the world as an aid to free discussion. The original rule was refined in October 1992 and again in 2002.
Meetings, or parts of meetings, may be held either "on the record" or "under the Chatham House Rule". In the latter case, the participants are understood to have agreed that it would be conducive to free discussion that they should be subject to the rule for the relevant part of the meeting. The success of the rule may depend on it being considered morally binding, particularly in circumstances where a failure to comply with the rule may result in no sanction.
The Rule allows people to speak as individuals, and to express views that may not be those of their organizations, and therefore it encourages free discussion. Speakers are then free to voice their own opinions, without concern for their personal reputation or their official duties and affiliations.
The Chatham House Rule resolves a boundary problem faced by many communities of practice, in that it permits acknowledgment of the community or conversation while protecting the freedom of interaction that is necessary for the community to carry out its conversations.