'The British attorney general has circulated legal advice to the prime minister’s office, Foreign Office and Defense Ministry warning that a preemptive military strike on Iran could violate international law, the Guardian’s Nick Hopkins reports. The existence of this secret document suggests that the U.K. government believes that Iran does not currently meet the legal threshold for a “clear and present danger” that would merit such an attack.

Though Iran’s illegal uranium enrichment is moving it closer to the capability to assemble a nuclear weapon, U.S. intelligence agencies do not believe that Tehran has affirmatively decided to build a bomb. The British legal memo would seem to underscore this view, as well as raise the question of whether Iran would have to cross that line for a military strike to meet the requirements of international law.

The Guardian also reveals that the U.K. is using this legal document to deny the U.S. assistance in contingency planning for a strike on Iran. The U.S. is reportedly asking for access to British airbases that are strategically located on remote islands.'

Read more: The U.K. Thinks a Strike on Iran Would Be Illegal, Denies U.S. Access to its Bases