After the NPT came into force in 1970, the International Atomic Energy Agency (IAEA) drew up a safeguards system to cover the entire nuclear industries (the ‘nuclear fuel cycles’) of the non-nuclear-weapon states that would join the treaty. 1 At that time the chief targets of safeguards were Germany and Japan, each still suspect in the eyes of several of its neighbours and each of which had an ambitious nuclear programme, including the construction of large enrichment and reprocessing plants able to produce nuclear-weapons material. The chief political aim of the IAEA’s NPT safeguards was therefore to verify that Germany and Japan did not divert nuclear material in any of the plants that they were required to put under safeguards when they joined the NPT; in other words, the safeguards were chiefly designed to apply to declared nuclear plants, and all such had to be declared.