It is one of the most powerful and dangerous jobs in the world and, for decades, foreign politicians, academics and spies have speculated over who will one day succeed to it. It brings absolute power over 24 million people, the command of a fanatical, nuclear-equipped army of a million men, and a brutal state security apparatus.

Today the man who is likely to inherit it emerged from the shadows – a little-known 25-year-old with a private education in Switzerland and fondness for sushi, German cars and

Reports from North and South Korea appear to confirm what until now has been only rumour – that Kim Jong Un, the third and youngest son of the North Korean leader, Kim Jong Il, is being lined up to inherit his father’s title. It would be the second hereditary succession in the last remaining totalitarian communist dictatorship – and set the scene for a period of extreme instability in one of the world’s most unpredictable countries.

Today one of his closest and most hardline generals promised the army’s loyalty to the “bloodline” of the senior Mr Kim, a virtual guarantee that one of his children will succeed to the leadership. Meanwhile, the South Korean Yonhap news agency quoted sources in China saying that Jong Un, the youngest of his three sons, will stand in a carefully rigged “election” to the country’s tame parliament – the precursor to his public emergence as his father’s successor.

“We will firmly carry on the bloodline of Mangyongdae and Mt Paektu with our guns, faithfully upholding the leadership of our supreme commander,” Pak Jae Kyong, a senior general of the North Korean defence ministry, was quoted in the state media as having told a rally to celebrate the recent birthday of Kim Jong Il. Mt Paektu is the scared Korean mountain where Kim Jong Il, according to the cult of personality that surrounds him, was born 67 years ago. Mangyongdae was the family home of his late father, the founder of North Korea, Kim Il Sung.

Yonhap quoted sources in Beijing saying that Jong Un had registered as a candidate in elections on March 8 for North Korea’s Supreme People’s Assembly. “Kim Jong Un will be formally nominated as successor after the elections,” one source told the news agency. “He is expected to take on key party and military posts in April.”

Foreign concern about the North Korean succession has been intense since last summer, when Kim Jong Il disappeared from public view for three months after apparently suffering a stroke. During his convalescence, his 62-year-old brother-in-law, Chang Sung Taek, is said to have taken over his responsibilities. It is still possible that Jong Un may eventually serve as no more than a figurehead while real power lies with older and more experienced leaders.

Jong Un was born in 1983 and, as the youngest of three known sons of Kim Jong Il, he might have been expected to remain subordinate to his older brothers, in keeping with Confucian tradition. His half-brother, Jong Nam, is 37 or 38, the son of his father’s first wife, a famous North Korean film star, who died in exile in 2002 after separating from Mr Kim. In 2001 he suffered humiliation when he was detained for travelling in Japan on a trip to visit Tokyo Disneyland with his family. He is occasionally spotted in the Chinese gambling enclave of Macao.

Jong Un and his 28-year-old brother, Jong Chul, were born to Koh Young Hee, a Japanese-Korean dancer. Before her death in 2004, state media had referred to her as “respected mother”, suggesting that one of her boys was being groomed for the leadership.

All the sons were educated in an exclusive private boarding school in Switzerland. According to Kenji Fujimoto, a Japanese who worked as personal sushi chef to Kim Jong Il and knew both the young “princes” well, it was obvious from his childhood that Jong Un would eventually take over from his father. “The older brother, Jong Chul, had the warm heart of a girl,” he told The Times last night. “The younger prince, Jong Un was a boy of inner strength.”

As teenagers, the boys played basketball and, even after casual games among friends, Jong Un would coach his team mates and analyse the successes and failures of their matches. “The first time I met him he was seven years old, and he looked at me as if I was an evil Japanese who had done terrible things to Koreans in the war,” said Mr Fujimoto. “I was impressed that even as a young boy he tried to analyse people he met.”

As a boy, Jong Un drove a Mercedes Benz with specially adapted pedals and seat around the grounds of Kim Jong Il’s home. He liked Chinese food and sushi, especially squid and the finest cuts of tuna. He used to smoke Mr Fujimoto’s menthol cigarettes

“If power is to be handed over then Jong Un is the best for it,” Mr Fujimoto said. “He has superb physical gifts, is a big drinker and never admits defeat.” TIMES ONLINE