Wen Jiabao must be quietly cursing Jimmy Carter. After the former US president travelled to North Korea earlier this month, he stopped off in Beijing on the way home. As Mr Carter later revealed on his website, the Chinese premier surprised him by saying that Kim Jong-il had described the idea of promoting his son as “a false rumour from the west”.

The news that Kim Jong-eun has been appointed a four-star general is the clearest indication yet that the ailing North Korean leader is starting to prepare the way for his third son to take over.

Mr Kim has made two visits to China in the past four months, the second one – in the view of most analysts in China – to brief Beijing on the Workers’ party congress. As a result, it is highly unlikely Mr Wen was surprised by Monday night’s announcement.