Your question stems from a statutory mentality, because statutes are country-specific. Natural Law Trusts, by contrast, are universal. If the trust were a statutory one, then it would be relevant to find out specifically for clients in which countries such trusts have been created. But the fact that it is NOT statutory, but rather is operating on the higher and more evolved plane of natural law, meaning that it this is not a necessary question for you to ask. Suffice it to say, good Natural Law Trust writers are world travelers and have clients in many countries. Natural law goes everywhere. Hence it is not necessary to determine whether the trust is applicable to any country in particular.
