The carefully choreographed reunion was part of three days of meetings between family members who have been divided for decades.

Kim Young-nam threw his arms around his wheelchair-bound mother and told her: “Stop crying. Why are you crying on such a happy day?”

“You look just like you used to,” she replied.

Meeting her daughter-in-law and seven-year-old grandson for the first time, Choi Kye Wol, 82, was overcome with emotion. “I have nothing left to wish for now,” she said between sobs.

Then she came face to face with Hye Gyeong, her 19-year-old granddaughter whose very existence is a contentious issue in neighbouring Japan. Many people are convinced that the girl’s mother was Kim’s first wife, Megumi Yokota, a Japanese girl snatched by North Korean agents when she was 13. Pyongyang insists that she committed suicide in 1994, but most people in Japan refuse to believe that she is dead.

Megumi’s true fate continues to fuel a bitter dispute between Japan and North Korea. Hye Gyeong offered no clue about who or where her real mother was.

Hundreds of South Korean and Japanese youngsters are thought to have been abducted by the Pyongyang regime, many used to train spies.

Mr Kim’s appearance offered their grief-stricken families a rare glimmer of hope of new information about some of the other abductees.

The last time Mrs Choi saw her son was in 1978. The 16-year-old schoolboy was playing on a beach in the South Korean coastal town of Kunsan when he was snatched by North Korean agents. Along with a suspected 480 other South Korean abductees, he disappeared into the Stalinist regime. Few of the abductees have seen their families again.

The tearful reunion took place in the mountain resort of Kumgang in North Korea, which is still technically at war with the South.

When Mr Kim asked his mother about the whereabouts of his father, Mrs Choi told him that he had died 20 years ago from grief at the abduction. The subject was quickly changed.

Experts in Seoul believe that after some years living in Pyongyang, Mr Kim married Yokota who bore him a daughter — DNA tests conducted this year provide convincing evidence for this. The North maintains that Yokota, depressed and in a mental institution, hanged herself. Three years later, Kim is thought to have married Park Chun-hwa, who appeared by his side. South Korean officials hold out little hope that Mr Kim will divulge much new information and argue that Pyongyang would not have let Mr Kim appear at all if they had not primed him with lines and were not certain that he would say the right thing.

“The North Korean side seems to have a lot to say through Kim’s mouth,” a South Korean diplomat said.

Seoul believes that more than 480 South Korean kidnap victims are still being held in North Korea, in addition to nearly 600 South Korean soldiers taken prisoner during the 1950-53 Korean War. Pyongyang says that any South Koreans in its country defected voluntarily, but in 1997 a North Korean spy, Kim Gwang Hyeon, admitted to kidnapping Kim Young Nam.

In 2002 North Korea admitted that it had abducted 13 Japanese citizens over the years to help to train spies in Japanese language and culture, and allowed five to return home. Pyongyang maintains that the other eight, including Megumi Yokota, are dead.

Charles Jenkins, an American soldier who deserted his Army unit in 1965 and fled to the North, was kept by the regime for 39 years and forced to make propaganda films. He married Hitomi Soga, a Japanese woman abducted when she was 19.

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