In his acclaimed book The Sleepwalkers, Christopher Clark wrote about how the great powers of 1914 stumbled into a pan-European war that not only destroyed much of the continent, but unleashed destructive forces that defined the global order for much of the following century.

Some of us fear that we are sleepwalking again, blindly unaware of the abyss that lies ahead. As a Chinese friend reminded me recently, war has its own logic. So too do crises. History teaches us they are both hard to stop once they start.

The greatest global flash point today is the Korean peninsula. Most analysts regard crisis and conflict over the North Korean nuclear programme as improbable. They are right. But the uncomfortable truth is that it is now becoming more possible.