For more than a decade, attempts to cajole, coerce or cold-shoulder the North Korean regime into relinquishing its nuclear ambitions foundered, as successive administrations in Washington demanded either too little or too much from Pyongyang.

While its neighbours in north-east Asia fretted throughout that period, it took a provocative nuclear missile test unleashed last October by the administration of Kim Jong-il, the North’s despotic leader, to prompt the US and others to try again to put a lid on his atomic capabilities. Only four months on, there is a deal – indeed, one that could represent a turning point in the long-running crisis.