Alastair Sim would appear in another adaptation of Edgar Wallace the following year, "The Terror."
The pun about "What war, Dad?" would have meant the Great War (WWI), but to British audiences, it might have been a premonition of what was brewing in Europe. WWII was on the horizon.
This film was included in the first syndicated television presentation of a package of major studio feature films on USA television; it premiered in St. Louis Sunday 6 June 1948 on KSD (Channel 5), in Detroit 22 June 1948 on WWJ (Channel 4), in Buffalo Sunday 4 July 1948 on WBEN (Channel 4), in Philadelphia Friday 16 July 1948 on WFIL (Channel 6), in Boston Sunday 25 July 1948 on WBZ (Channel 4), in Chicago Sunday 1 August 1948 on WGN (Channel 9), in both New York City and Cleveland Sunday 22 August 1948 on WPIX (Channel 11) and on WEWS (Channel 5), in Milwaukee Sunday 5 September 1948 on WTMJ (Channel 3), in Los Angeles 30 November 1948 on KTLA (Channel 5), and in Baltimore Saturday 15 January 1949 on WMAR (Channel 2). The package consisted of 24 Alexander Korda productions originally released theatrically between 1933 and 1942.
In British slang, a "sqeaker" is an informant - like a "stool pigeon" in American slang.