The best intelligence available suggests Kim Jong-il, leader of that most roguish of rogue states, is semi-paralysed after suffering a stroke. But when it comes to dealing with potential regime change in North Korea, western leaders find themselves in little better condition.

Paralysis in contemplating who might follow the Dear Leader is worrying. North Korea’s nuclear programme may be primitive. But if an unpredictable succession struggle erupted, that would be small comfort to neighbours. With the world’s fifth-biggest standing army and millions of its hungriest and most downtrodden people, a collapsing North Korea could play havoc with regional stability.