When British WW2 veterans turned their back on the Japanese Emperor

It was a silent, poignant protest. Spurning an appeal from then Prime Minister Tony Blair, hundreds of British veterans of the Second World War pointedly turned their backs on the Japanese Emperor Akihito as he visited London and Cardiff in 1998. In a previous state visit in 1971, Akihito's father, Emperor Hirohito, met with a similar response. At Claridge's Hotel in London, the son of a prisoner of war who had died at Japanese hands barracked him - and a tree Hirohito planted at Kew Gardens was found cut down the following day, with a sign declaring: "They did not die in vain."

The source of such bitter hostility lay decades earlier, in the war in the Far East. In the months after Japan's attack on America's Pacific Fleet at Pearl Harbor on December 7, 1941, Hong Kong, Malaya, Singapore, Burma, the Dutch East Indies (now Indonesia) and the Philippines (then a US protectorate) fell like dominoes.

As a result, around 300,000 Allied soldiers, sailors and airmen fell into Japanese hands as prisoners of war (POWs). And many more civilians too, including women and children. This was a Japanese victory on a stupefying scale and, in the Far East and the Pacific, the course of the war was largely set by the need to halt and reverse this spectacular tide of conquest.

But the resentment shown in these state visits did not arise from the shame and humiliation of the vanquished - but from the treatment they received as POWs. While large numbers of Indian soldiers were cajoled or coerced into joining the pro-Japanese, pro-independence Indian National Army, the bulk of prisoners were treated as a vast and expendable labour force - put to work, regardless of the human cost, in consolidating Japan's "Greater East Asia Co-Prosperity Sphere".

As General Hideki Tojo, Japan's prime minister from 1941 to 1944, put it, POWs would not be "permitted to eat the bread of idleness". The practice of putting POWs to work was a well-established principle under international law, but the conditions led to suffering on a colossal scale. One stark statistic underlines the nature of this ordeal: just 4% of British, American and Commonwealth POWs captured by the Germans died in captivity. In contrast, the mortality rate among the 140,000 European, Australian and North American POWs in Japanese hands - 50,000 of them British - spiralled to 27%.

However, this figure cannot convey the ordeal of those who survived the hunger and squalor of the prison camps; dangerous forced labour in mines, shipyards, and factories; and the terror of the "hellships", which, despite the deadly threat of air or submarine attack, criss-crossed the Pacific Ocean with their human cargoes.

The building of the Burma Railway became the ultimate emblem of the suffering and privations of Allied Far East Prisoners of War (FEPOWs).

Built to supply Japanese forces in Burma, this was constructed between Nong Pladuk in Thailand (then a Japanese ally) and Thanbyuzayat in Burma and was pushed over more than 250 miles of mountainous and disease-ridden jungle between the summer of 1942 and the autumn of 1943. Wretchedly equipped, severely malnourished and wracked by malaria, cholera, dysentery and other diseases, one fifth of the 61,000 British, Australian, American and Dutch POWs employed on the "Railway of Death" perished before its completion.

But conspicuous throughout these years was the brutality and capriciousness of the Japanese themselves. Various reasons have been given for their conduct.

Besides the maladministration and chronic supply problems which plagued Japan's far-flung war effort (in New Guinea, Japanese soldiers even resorted to cannibalism), Japan had signed but had not ratified the Geneva Convention of 1929, so did not feel bound by its terms.

Infused by the unforgiving cult of Bushido (the "way of the warrior", signalled by the ubiquitous samurai swords worn by its officers), brutality was inherent in Japanese military culture: severe beatings were a means of enforcing discipline and suicide was expected rather than surrender. Seen as a flagrant dereliction of duty, surrender was expressly forbidden by the Field Service Code of the Imperial Japanese Army.

Even before Pearl Harbor, the implications of this culture had become apparent in Japan's brutal war of conquest in China, which had seen the 1937 "Rape of Nanjing", in which tens of thousands of Chinese civilians had been raped, tortured and murdered.

If the Japanese military had already shown its propensity to beat, shoot, and even decapitate its prisoners, a profound sense of racial superiority governed its conduct towards those it captured after Pearl Harbor. Military prisoners were held in contempt for surrendering, and the Japanese believed themselves to be a sacred race ruled by a divinity - an outlook that placed them above Europeans and other Asians.

As General Tomoyuki Yamashita - conqueror of Singapore and the so-called "Tiger of Malaya" - put it, the Japanese were descended from gods, whereas Europeans were descended from monkeys. If the deliberate parading of European POWs proclaimed the victory of the Japanese over the arrogant, racist, colonial European powers, their treatment of other Asians could be even worse. Despite the horrendous death toll among European POWs on the Burma Railway, the toll among Asian labourers (Indonesians, Malays, Tamils, Chinese and Burmese) was greater still, with more than 100,000 - half the Asian workforce - dying during its construction.

Japanese conduct was not uniformly savage, nor always inconsistent with the Geneva Convention. But even this was scant consolation.

Under the terms of the Convention, for example, POWs were entitled to send and receive mail. Though not a priority for their captors, some FEPOWs did send and receive morsels of news, though many others did not. As one desperate woman, whose husband had been captured during the surrender of Singapore in February 1942, put it: "One feels so helpless, as if the earth had swallowed them all up."

Similarly, the Japanese welcomed Red Cross visitors to their model officers' camp at Zentsuji in Japan, whose privileged inmates (a tiny fraction of all FEPOWs) received regular distributions of Red Cross parcels and were permitted to roam outside the camp. For the vast majority, however, their years of captivity were ones of deprivation, degradation and suffering. Given their plight and location, escape was usually all but impossible and survival a matter of sheer perseverance and endurance. It was not always a story of heroic solidarity, however.

One prisoner testified that, at Chungkai on the Burma Railway, the "law of the jungle" prevailed among desperate POWs before a semblance of order and cohesion was restored: the bodies of the dead were not even decently buried.

In hellish conditions that were prone to lay bare the extremes of good and evil, and as products of self-consciously Christian societies, faith played an important role for many survivors.

According to Eric Lomax, author of bestselling memoir The Railway Man and a strict Baptist when captured at Singapore, "the moral conviction of being saved, that I really had found God, helped me to survive what came later".

For others, such as Jack Chalker and Ronald Searle on the Burma Railway, their sketches and paintings supplied (in the absence of cameras) a crucial sense of purpose in bearing witness to their staggering ordeal. There were also outstanding examples of leadership.

Before his death from malnutrition and diphtheria in November 1942, Major-General Merton Beckwith-Smith sponsored sports, the building of a theatre and even the creation of a local university among prisoners of the British 18th Division in Changi on Singapore Island. One of his protegés, Lieutenant-Colonel Philip Toosey, went on to provide equally inspiring leadership on the Burma Railway. Although fears of a wholesale massacre of surviving FEPOWs were not realised, for them the war did not come to an end with Japan's surrender.

Returning to Britain more as victims than as victors, they were instructed to remain silent about their experiences to spare the distress of those whose husbands, fathers and sons did not return.

In the moment of victory, their previous defeats were not to be dwelt upon and, in the strategic context of the Cold War, the sins of the Japanese seemed to be rapidly absolved. Only with the release of David Lean's film The Bridge on the River Kwai (1957) did their experience receive the exposure it deserved. Despite decades of campaigning, compensation from the Japanese and British governments proved meagre and tardy, with many FEPOWs not living to qualify for the £10,000 ex-gratia payments in late 2000.

Instead, the physical, emotional and psychological costs of their captivity continued to be borne into old age. Faced with such sluggishness and post-war amnesia, well might they have chosen to turn their backs.

• Professor Michael Snape is author of Forgotten Warrior: The Life and Times of Major-General Merton Beckwith-Smith 1890-1942 (SPCK Publishing, £29.99)