The judge also said that the law "impermissibly attempts to circumscribe a court's ability to review the necessity of nondisclosure orders, " violating the principle that allows the judicial branch to review laws and executive actions.
No judicial decision or applicable treaty contradicts this principle, and the U.S. Supreme Court has established that works of international legal scholars can be acceptable as evidence of the law.
Robert Jay QC, for inquiry chairman Lord Justice Leveson, said the application for a judicial review was "premature" as the chairman had only agreed in principle to receive anonymous evidence.
On Monday, Argentine President Cristina Fernandez de Kirchner called the agreement to set up a judicial commission "historic", saying it guaranteed "the right to due process of law, a fundamental principle of international criminal law".