Just been on TPTV (have as a DVD too) and qualifies here as a comedy film - AND HOW!
What can I say? Alastair Sim, utterly and simply superb.
With a host of wonderful actors of the day - Terry-Thomas and George Cole as the front runners, along with the wonderfully dotty Dora Bryan, Raymond Huntley, Richard Wattis, Mr. Grainger ( Arthur Brough from Are You Being Served?), Arthur Lowe as Radio Shop Owner, Peter Bull, Willoughby Goddard, Michael Ripper (another "Sam Kydd" type) and an uncredited Terence Alexander in a very minor part.
Now I'm going to be terribly picky here but there is just one tiny, tiny flaw in the plot for me and that is that the gorgeous Jill Adams (whose house it is that is next door and is "borrowed" by Alastair's henchman/bomb maker for ...............well, spoiler alert just in case somebody hasn't seen it yet...................) puts up a hell of a lot from the potty George Cole's vacuum cleaner salesman TWICE and any sane person would have dialled 999 the first time, instead of THEN going off with him to "solve" the case.
Just sayin'
Otherwise, VERY FUNNY all the way through and if you haven't seen it, then you must!