Anachronisms: During the Morant trial, a military band is heard playing Elgar's "Pomp and Circumstance March No. 1." The march was premiered in England in October 1901, and it is very unlikely that an arrangement for military band was available less than two months later when the trial took place. It wasn't until later in 1902 that the words "Land of Hope and Glory" became permanently wedded to the tune.
Revealing mistakes: In the closeup of a soldier's finger pulling the trigger of his Enfield rifle during Lt Morant's explanation of "Rule 303" to the court, the rifle stays absolutely still when the shot goes off. In actuality, a high-powered rifle like the .303-caliber Enfield would "jump" noticeably at the instant of firing.