"The Firing Squad" is a 1955 episode of the TV series Four Star Playhouse. It was based on the classic Canadian novel Execution. It was relocated to be set in the Australian army in World War Two, one of the rare depictions of Australia in Hollywood at the time.
In World War Two, a disgraced officer, Captain Adams, is ordered to lead a firing squad to execute a deserter, Jones who has been accused of murder. Jones is generally agreed to be innocent, but the army have decided to shoot him as an example.
In the Los Angeles Times Niven describes his character as Canadian. But in the final play his character is Australian.