The dark horse in the family succession stakes is Kim Jong-il’s brother-in-law, Jang Song-taek. He has two major factors in his favor - he is more mature in years than his nephews and he runs the country's internal security system.
Kim Jong-il’s eldest son Kim Jong-nam, 37, would usually have been regarded as the natural successor under Confucian tradition. But the playboy with a penchant for discos, casinos and brothels caused an embarrassing scandal for Pyongyang when he was caught trying to sneak into Japan on a fake Dominican passport in 2001.
His other two known sons are Kim Jong-chol, 27, and Kim Jong-Un, 25, the children of the Japanese-born star of Pyongyang's most famous song-and-dance troupe. (Kim Jong-il's former sushi chef Kenji Fujimoto, who defected to Japan, has said that Jong-un is the most favored of the three sons because of his striking resemblance to his father - a serious advantage in the eyes of a famously vain figure.)
But neither has any public profile or is known to have held any significant positions in the military or party. And in a society that places high importance on age and wisdom, it is unlikely that such young men could fulfil even a symbolic leadership role.
In a worst-case scenario, different Kim relatives could be backed by rival factions. In 2006, South Korea's intelligence service, which has a network of well-placed informants in Pyongyang, predicted that when the dictator died, a power battle would break out between top military officials - in partnership with the dictator's sons.
[Excerpt of an article by Philip Sherwell and Stanlislav Varivoda, The Telegraph]