The River Kwai, in fact, does not exist; Tamakam Bridge crosses the greater branch of the River Mekong. The bridge of the film was located near the Burma border, 250 kilometres to the northwest from Tamakam. The bridge the tourists now look at was the second bridge built from Tamakam Camp, finished in mid-1944, and put out of action by the RAF early in 1945. The first temporary, wooden one has disappeared. I questioned many ‘Free Thai’ members of Force 136, but none know of any attempt to sabotage Tamakam Bridge; it would have been pure suicide in such open country.

As regards Colonel Nicholson, the hero of the film, doctors who were there say that not many men went mad, despite our appalling conditions. If a British colonel had gone insane, his men, far from gladly following him into collaboration, would universally have called him a ‘Jap-happy bastard’ and a doctor would either have tucked him away in the hospital as mentally sick, or he might have met with a more violent fate from one of the men whom, in the film, he drove from the hospital to work on the line.

The Thai State Railways had provided us with small, self-driven trolley cars with trailers to use up and down the line. About one hundred kilometres of POW-built railway still exist, ending now at a place called Nam Tok – which means waterfall – where the headquarters camp of another group of POWs used to be, commanded by my own commanding officer, Lieutenant Colonel Knights.

As we sped up country, nearing the great viaduct, at Wang Po – which is an eight-hundred-yard-long piece of bridging and cutting – and followed a sheer cliff face round a wide escarpment, with the river roaring one hundred feet below, Nagase shouted above the clatter of the engine: ‘We Japanese who built this railway think it’s the best in the world. We are very proud of it!’

We Japanese who built the railway! Hell, we built the railway! But then, as the train rattled along, for the first time I assimilated this new viewpoint. I thought: I suppose, yes, we were really just the labourers. No Nicholson emerged to build fantastic bridges with geniuses of Indian pukka sahibs, followed by their docile and adoring men. The Japanese engineers planned the whole thing and saw that their plans were carried out – by us. In ordinary industrial terms, management and workers. For the first time, I saw how trade unionists feel.

Wang Po still stands, and many of the original teak balks seem to be in use. Trains cross it at a cautious five miles an hour. It may have looked in 1943 like an Emmett bridge, shored up with thousands of temporary buttresses, but it was built in less than six months, and I saw a train cross it in April 1943. Very formidable and practical engineers, the Japanese – not only now, but even then.