The matter eventually worked its way to the Prime Minister, Neville Chamberlain, who wrote personally to President Roosevelt asking for the Norden, but even this was rejected. The reason for these rejections was more political than technical, but the U.S. Navy's demands for secrecy were certainly important. They repeated that the design would be released only if the British could demonstrate the basic concept was common knowledge, and therefore not a concern if it fell into German hands. The British failed to convince them, even after offering to equip their examples with a variety of self-destruct devices.