When I first saw this film I was somewhat amazed by what appeared to be a lazy construction. The first half of it, leading to the armored car robbery, was fairly straightforward, as "Professor" Marcus and his cronies put together their plan, and carry it out, with little Mrs. Wilberforce used as an unwitting courier of the cash. But from the end of the robbery to the conclusion the film seems to straggle on. It is only upon watching it three or four times that the mutual destruction of the criminals makes more and more sense, and the permanent victory of the little old lady caps off the film very satisfactorily indeed.
Mrs. Wilberforce, elderly, crotchety (but in a gentle and genteel way), and very moral, is the personification of an earlier Britain - the Victorian/Edwardian period, where right was right and wrong was wrong. She is able to survive in her little corner of London because she is frail and the local authorities (the police represented by Jack Warner and Philip Stainton) "control her" by showing a degree of respect for her feelings and opinions. At the beginning of the film she is shown making her complaint (a daily occurrence) which they know are a nuisance and time-waster, but which they allow her the luxury to bring up. In her costume throughout the film, her real symbol is her umbrella. She always carries it, even when it is sunny out. The umbrella is a symbol of respect too - in one scene a police officer stops her to return the umbrella when she leaves it behind accidentally. Umbrellas are for protection, like Victorian morality is supposed to be. Interestingly enough, at the tail end of the film, when she is convinced by the police (who don't realize it) to keep the stolen money, her morality is dented, and she abandons her old umbrella.
Professor Marcus and his gang invade her home (peacefully, to be sure, as amateur musicians). They represent more modern times. Major Claude Courtney (Cecil Parker) is the military man, no longer a figure of respect but of shriveled honor - a comment (maybe) of the decline of the military and aristocracy and upper classes in 20th Century England. One Round and Harry are the urban proletariat - the uneducated lugs (although with a struggling morality that surprises them) and the "teddy boys" ready to break down society for fun and profit. Louis, with his vague foreign appearance and menace, is the waves of immigrants who have entered Britain, changing it's old courtesies and tolerance for age, honor, and justice. And Professor Marcus - he is a variant in the intelligentsia - an opportunist ready to get ahead by subterfuges (like pretending to play "Boccherini" quintets), and always ready with some sophistry as an argument (like his argument about the robbery boils down to some pittance added to the insurance premiums of England). They don't represent all of 20th Century England, but it is an intriguing cross section.
The film has lovely, unexpected charms to it. In the middle of planning the demise of Mrs. Wilberforce, Marcus and his cohorts (and Mrs. W.) find her elderly friends have come over for a weekly visit. For at least an hour or two these guests are in the house. Mrs. Wilberforce is as upset about it as Marcus and his gang, but her anger is at the thieves - she insists (as though they were going to do so) that they refrain from doing anything that would embarrass her before her oldest friends. Louis, the only one who is not there (he's parking the getaway car on a side street) returns to be handed a teacup, and to watch the others assisting the old ladies in the singing of "Silver Threads Among the Gold". Guinness's look of helplessness at the player piano is a sight to behold.
There are small treasures. When (at a moment of fear and excitement) Marcus , the Major, One Round, and Harry leave the bedroom, they accidentally leave the "Boccherini" piece playing on the record player. Louis has no intention of leaving to assist them (in feeding medicine to Mrs. Wilberforce's parrot), but just sits staring angrily into space, as the record continues playing. Then it starts skipping. Louis picks it up, looks at the label, and smashes the record he's come to hate.
Another great moment is when Mrs. Wilberforce starts reminiscing to the others of her coming out party on January 22, 1901. She describes how she was finely dressed up, and all her friends came, and they had a splendid time dancing and eating. Then came word from her father they had to end, because the old queen died. And everyone left. Miss Johnson relays that dialog with as sweet softness, which her age makes one momentarily remember the end of the Victorian age (for it is the death of Queen Victoria that ended her party). But after she leaves the room the entire effect is marvelously punctured by Danny Green (One-Round). Looking totally baffled, he turns to the others and asks, "What is she talking about? Old Queen Who?"
The film may not be the best "black comedy" in cinema (MONSIEUR VERDOUX and KIND HEARTS AND CORONETS are just as good choices for that slot) but it is in the top ten films of that type. And ten is what I give it here.