North Korea’s probable test of a nuclear weapon on Monday has triggered the second nuclear crisis in 13 years on the Korean peninsula.

In 1993, North Korea announced it would pull out of the Nuclear Non-Proliferation Treaty, leaving it free to divert nuclear material from its energy reactors to make a nuclear weapon and setting off a round of crisis diplomacy led by the Clinton administration. The result was the so-called agreed framework, which – in return for supplies of fuel oil to North Korea – froze most aspects of Pyongyang’s nuclear weapons programme for the rest of the decade.