After Eric stabs the debt collector in his front hallway, the others hold him back and the knife is seen clearly, but there is no blood on the knife.
When Eric hugs Patti in the final scene, his watch shows the time as about half past six despite it obviously being the middle of the day.
The Japanese flag flown during World War 2 is the "Rising Sun". All instances in this movie indicate the flag flown is the modern Japanese flag with a red sun in a white background. This would NOT have been flown during World War 2.
The POW camp is shown as being liberated by American paratroops. In reality it was liberated by mainly Indian infantry.
The motorcycle and sidecar should have the sidecar on the left, not the right.
The young Lomax shows the map to the soldiers and explains they've been on the POW train for four days before heading west, yet young Lomax is still clearly clean shaven and has no sign of stubble or growth.
Before the British POWs are loaded onto the train that will take them to work on the infamous Thai-Burma railway, near the beginning of the film, as they are counting off in playing card face-values "one, two, three...Jack, Queen, King, Ace", they pass radio components to each other behind their backs, but as there are multiple Japanese guards posted behind them on the roofs of the goods wagons, this smuggling action would have been easily observed, and the contraband confiscated.
When Eric and Patti first meet on the train, Eric eats his homemade lunch and drinks from his thermos cup. When he exits the train he leaves the thermos on the table.
When he goes up line to collect a bit of equipment for the radio the scene shows POWs working on the track with picks and sledge hammers though the track has clearly been laid for quite some time as there are weeds growing....
After the surrender of British forces in Singapore, the Union Flag is lowered, and the Nisshoki, or Hinomaru (red disk on a white field) is hoisted in its stead. However, as Singapore was being occupied by the Japanese military, and not, at this point, yet a part of the Japanese empire, the flag should have been the Kyokujitsu-ki, or 'Rising Sun' flag. The flags shown later, hanging from military vehicles, also Nisshoki, are correct, as Thailand had at this point been effectively annexed, and was now part of the Japanese Empire. The Thai-Japanese alliance was signed on December 21st, 1941.
When Eric meets Patti for the second time you can clearly see an LED style signal light in the background. These were not installed in the UK until the late-2000s.
Many of the train liveries shown in the UK were either long out of use by 1980 or in the case of the maroon West Coast Railway livery did not exist yet.
The Royal Border Bridge at Berwick-on-Tweed is shown with overhead wires, which were not built until 1989.
Young Eric tells Major York "Now the U.S. Air Force has joined in." The U.S. Air Force did not exist until 1947. It was the U.S. Army Air Forces that joined in bombing Germany.