Colonel March Investigates is a 1955 British film consisting of the three pilot episodes of the TV series Colonel March of Scotland Yard that were filmed in 1952, starring Boris Karloff. These episodes were Hot Money, Death In The Dressing Room and The New Invisible Man.
Boris Karloff and his wife Evelyn sailed to England in July, 1952, where Karloff filmed 3 different pilot episodes of the Colonel March series to show to British TV executives. In 1953, when the show was green lighted, Karloff returned to England to film 23 more episodes, making a total of 26 in all, then returned to Hollywood to film Abbott and Costello Meet Dr. Jekyll and Mr. Hyde (1953). The three pilots were later combined into the 1955 feature film called Colonel March Investigates (aka Colonel March of Scotland Yard), so that they could be shown theatrically.
The Colonel March TV series premiered in the United States in Feb., 1956. (It was broadcast from Feb. 1, 1956 through April 1, 1957, which included a number of re-run episodes.) British viewers only got to see it seven months later, as it premiered on the BBC in September, 1956.