When I was co-authoring 'Tax Havens: How Globalization Really Works' (Cornell Studies in Money) with Ronen Palan and Christian Chavagneux we faced a dilemma. It was that no one - ourselves included - had adequately defined a tax haven. I'd venture to suggest that this remains the case to date. That is why I took on the challenge of defining something else that could provide a policy basis for action - which was the secrecy jurisdiction.
I didn't create the term secrecy jurisdiction. I did define it. I said that secrecy jurisdictions are places that intentionally create regulation for the primary benefit and use of those not resident in their geographical domain. I added that this regulation is designed to undermine the legislation or regulation of another jurisdiction and that to facilitate its use secrecy jurisdictions also create a deliberate, legally backed veil of secrecy that ensures that those from outside the jurisdiction making use of its regulation cannot be identified to be doing so.
The term has since been widely adopted, and sometimes been reverse engineered to be a definition of a tax haven (as Nick Shaxson did in his book Treasure Islands, for example).
Let me assure you, the secrecy jurisdiction is not.
Cameron's claim is meaningless since he cannot define a tax haven. My claim is not. I can define a secrecy jurisdiction.