To follow-up on it a bit, whenever Western countries are put into a situation like that, they're effectively forced to do exactly what happened here. After all, whether or not something becomes public or not is completely outside of both parties' control. The minute some newspaper-person looked up the terms on the treaty and published it, there would have been an immediate international confrontation. So Britain was forced to come up with some kind of framework whether they wanted to or not -- simply to prevent random crises in the future.