Meet Mr. Callaghan

Meet Mr. Callaghan is a 1954 British crime drama film directed by Charles Saunders and starring Derrick De Marney. Based on the 1938 novel "The Urgent Hangman" by Peter Cheyney, which Cheyney had then turned into a play.
Co-producer and star Derrick de Marney had directed the stage version of "Meet Mr. Callaghan" at the Garrick Theatre in 1952, which starred Derrick's brother Terence as Cheyney's private eye Slim Callaghan. Derrick played this role in the film.
The play was notable for the theme music and score by Eric Spear which became a best-selling record for Les Paul.
Plot.
Down at heel private Detective Slim Callaghan (Derrick De Marney) is hired by young socialite Cynthis Meraulton (Harriette Johns) to investigate. When her rich stepfather changes his will in her favour, and is then subsequently murdered, suspicion falls on Cynthis.
Production.
Patrick Cheyney's novel "The Urgent Hangman" was published in 1938. It was the first in a series of novels by Cheyney featured private investigator Slim Callaghan, others including "Dangerous Curves" (1939), "You Can't Keep the Change" (1940), "It Couldn't Matter Less" (1941), "Sorry You've Been Troubled" (1942), "They Never Say When" (1944) and "Uneasy Terms" (1946). "Uneasy Terms" was turned into a 1948 film.
"The Urgent Hangman" was adapted by Gerald Verner into a play "Meet Mr Callaghan" which premiered at the Garrick Theatre in 1952. The role of Slim Callaghan was played by Terence De Marney and the production was directed by de Marney's brother Derrick. The play was very successful. It inspired a hit song.
Terence De Marney played Callaghan in another Gerald Verne theatrical adaptation of a Callagahan story, "Dangerous Curves", which premiered at the Garrick in 1953.
In the film version of "Meet Mr Callaghan", the role of Slim Callaghan was played by Derrick de Marney, not Terence. Filming took place at Nettleford Studios in September 1953.
It was the second film from Belinda Lee.
Critical reception.
"Monthly Film Bulletin" said the "transference" from stage to screen "has been made without much imagination. The involved plot is helped along by a few barbed lines but Derrick de Marney fails to make a sympathetic hero out of a private detective who stoops to robbery, blackmail and bribery in his investigations."
"TV Guide" wrote, "Mystery programmer has a couple of good moments, but little else": whereas "MysteryFile" noted, "The detective work is very good, and the complicated plot holds together, but it's the overall sense of good humor that really carries the day — not laugh out loud funny, but the mood is light enough to smile almost constantly."