Some fantastic film making, despite the revisionist history and the ridiculous role of William Holden. The ending is highly symbolic. It isn’t really about the Colonel, played by Alec Guinness, not wanting the bridge to be destroyed by the British commandos and the American. In reality, of course, he would want the bridge to be destroyed and not impede the efforts of their secret mission. But this is a movie. What the Colonel represents is the British Empire and the desire to let the bridge survive with the expectation that Britain would not only win, but the bridge would still be standing for the glory of the Empire. This is one of the reasons the Colonel mentions his love of India and why he is intrigued by the idea of using trees that would last six hundred years.
Unfortunately, this is done at the actual expense of a fine commander, whom was not like the person depicted at the end of the film. Despite this bastardization, his death in the film and his accidental falling upon the lever is a metaphor for the end of the British Empire and colonialism, although it is a bit blatant and contrived how he dies and coincidentally falls on the charge. The Japanese counterpart and his plan for suicide, as well as the train crashing into the river, is also a metaphor for the end of Imperial Japan.
I view William Holden as a surrogate for David Lean. Holden was essentially a soapbox figure mouthing off at every chance he got about some issue he had about the war. From the standpoint of believability, the character was unbelievable. Despite this nonsense, I liked Holden’s role in the film.
In real life, the bridge was not destroyed by a commando team, rather it was later bombed by American airpower, the Japanese were incredibly brutal in Indochina, there was never an American on the Brit commando team and both the Colonel and his Japanese counterpart lived. Just minor little details on a film loosely based on a book by a French guy writing about the British in Japanese occupied Indochina with a Canadian thrown in for good measure.