The former President George HW Bush narrowly escaped being beheaded and eaten by Japanese soldiers when he was shot down over the Pacific in the Second World War, a shocking new history published in America has revealed.

The book, Flyboys, is the result of historical detective work by James Bradley, whose father was among the marines later photographed raising the flag over the island of Iwo Jima.

Lt George Bush, then a 20-year-old pilot, was among nine airmen who escaped from their planes after being shot down during bombing raids on Chichi Jima, a tiny island 700 miles south of Tokyo, in September 1944 - and was the only one to evade capture by the Japanese.

George HW Bush, pictured in early 1943 as a naval aviator cadet credit: Photoshot

The horrific fate of the other eight "flyboys" was established in subsequent war crimes trials on the island of Guam, but details were sealed in top secret files in Washington to spare their families distress.

Mr Bradley has established that they were tortured, beaten and then executed, either by beheading with swords or by multiple stab-wounds from bayonets and sharpened bamboo stakes. Four were then butchered by the island garrison's surgeons and their livers and meat from their thighs eaten by senior Japanese officers.

The future president escaped a similar fate because he ditched his plane further from the island than the other crews, and managed to scramble on to a liferaft. American planes launched a hail of fire at Japanese boats which set out to capture him, driving them back, and he was eventually rescued by a US submarine.

When the black hull of the USS Finback surfaced in front of him, he thought he was hallucinating, he told Mr Bradley in a television film made to coincide with the publication of Flyboys. He had been vomiting, bleeding from a head wound, and weeping with fear. He said only four words to his rescuers: "Happy to be aboard."

Mr Bush's part in the raid - for which he won the Distinguished Flying Cross - has long been known to Americans. Not known until now was the grim fate of his downed comrades - none from his own plane - who swam ashore.

Navy pilot George Bush sits in a VT-51 Avenger in 1944 credit: Caters

Mr Bradley pieced together the horrific truth from secret transcripts of the war crimes trials, given to him by a former officer and lawyer who was an official witness at the time, and the testimony of surviving Japanese veterans.

A radio operator, Marve Mershon, was marched to a freshly dug grave, blindfolded, and made to kneel for beheading by sword, testified a Japanese soldier, named as Iwakawa, at the war crimes trial. "When the flyer was struck, he did not cry out, but made a slight groan."

The next day a Japanese officer, Major Sueo Matoba, decided to include American flesh in a sake-fuelled feast he laid on for officers including the commander-in-chief on the island, Gen Yoshio Tachibana. Both men were later tried and executed for war crimes.

Downed pilot George Bush is rescued by the Navy submarine, USS Finback on September 2, 1944 credit: Photoshot

A Japanese medical orderly who helped the surgeon prepare the ingredients said: "Dr Teraki cut open the chest and took out the liver. I removed a piece of flesh from the flyer's thigh, weighing about six pounds and measuring four inches wide, about a foot long."

Another crewman, Floyd Hall, met a similar fate. Adml Kinizo Mori, the senior naval officer on Chichi Jima, told the court that Major Matoba brought "a delicacy" to a party at his quarters - a specially prepared dish of Floyd Hall's liver.

According to Adml Mori, Matoba told him: "I had it pierced with bamboo sticks and cooked with soy sauce and vegetables." They ate it in "very small pieces", believing it "good medicine for the stomach", the admiral recalled.

US Navy pilot George Bush sits in the cockpit of an Avenger fighter aircraft, c. 1943-45 credit: Caters

A third victim of cannibalism, Jimmy Dye, had been put to work as a translator when, several weeks later, Capt Shizuo Yoshii - who was later tried and executed - called for his liver to be served at a party for fellow officers. Parts of a fourth airman, Warren Earl Vaughn, were also eaten and the remaining four were executed, one by being clubbed to death.

The parents of all the airmen are now dead, but Mr Bradley contacted all their families. "The first reaction was a stunned silence, a hush. But I think that at last knowing how these men died, however horrible their deaths, has allowed closure and in a word I heard from them, healing," he said.

Mr Bush's first reaction was also to say nothing. "There was a lot of head-shaking, a lot of silence," the author told The Telegraph. "There was no disgust, shock or horror. He's a veteran of a different generation."

The former president returned to Chichi Jima with Mr Bradley for the first time since his rescue for the CNN documentary broadcast last week. Mr Bush looked sombre but never visibly upset, and ventured into the water in a modern liferaft to re-create his experience.

George HW Bush's service dog pays his respects to his master

He recalled that while on the submarine he asked himself why he had survived. "Why had I been spared and what did God have in store for me? In my own view there's got to be some kind of destiny and I was being spared for something on Earth." Earlier he had told Mr Bradley: "I think about those guys all the time."

This article was originally published on October 26, 2003