Is Kim Jong-il for real? The question has baffled foreign intelligence agencies for years but now a veteran Japanese expert on North Korea says the “dear leader” is actually dead – and his role is played by a double.

The expert says Kim died of diabetes in 2003 and world leaders including Vladimir Putin of Russia and Hu Jintao of China have been negotiating with an impostor.

He believes that Kim, fearing assassination, had groomed up to four lookalikes to act as substitutes at public events. One underwent plastic surgery to make his appearance more convincing. Now, the expert claims, the actors are brought on stage whenever required to persuade the masses that Kim is alive.

The author has been derided by rival analysts of the hermetic communist state. Yet so few facts are known about North Korea’s ruling dynasty that some of the strange things reported in Professor Toshimitsu Shigemura’s bestselling book cannot be readily explained.

“Scholars don’t trust my reasoning but intelligence people see the possibility that it will turn out to be accurate,” he said. “I have identified and pinned down every source.”

The book, The True Character of Kim Jong-il, cites sources from inside North Korea and from the intelligence services of Japan and South Korea.

One of its principal claims is that a voiceprint analysis of Kim’s speech at a 2004 meeting with Junichiro Koizumi, then the Japanese prime minister, did not match an authenticated earlier recording.

His book traces Kim’s supposed demise to autumn 2003 when he vanished for about 42 days. Most analysts put this down to mourning for one of his wives, a power struggle inside the Kim dynasty or fear of an American strike.

Kim’s poor health has been the subject of speculation for decades. The professor’s contribution is to cite Russian and Chinese sources saying he had diabetes and illnesses of the heart, liver and lungs, with depression thrown in.

There have been persistent reports that a stand-in appears for Kim at military parades and he is notoriously reclusive. He did not appear in public to receive the Olympic torch in Pyongyang on April 28.

The professor argues that no substantive policy decisions have been taken since North Korea joined nuclear disarmament talks in 2003.

South Korean analysts who attended two summits with Kim (before and after his supposed death) reported that he had indeed changed appearance. But that was because he had lost weight, quit smoking, given up cognac in favour of red bordeaux and coaxed the rest of the politburo onto a health kick.

Additional reporting: Shota Ushio, Tokyo

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