not my favorite. not a lot to the guinness character. the comedy is mostly mild slapstick and class harrumphery. bfi has it listed as the 58th greatest british film of all time so ymmv.
maybe the twist is that both rich and poor alike see his invention as a threat to their livelihoods and form an uneasy alliance to suppress it. imagine these ealing comedies were not viewing themselves as anything more than workaday entertainments that have taken on the gloss of statement films when the study of film elevated them beyond their station.
It followed a common Ealing Studios theme of the "common man" against the Establishment. In this instance the hero falls foul of both trade unions and the wealthy mill owners who attempt to suppress his invention.
The films chided the idiosyncrasies of English institutions. Ealing producer Michael Balcon stated, “If you think about Ealing at those times, we were a bundle...(I'm not saying this in any critical sense), we were middle-class people brought up with middle-class backgrounds and rather conventional educations. Though we were radical in our points of view, we did not want to tear down institutions: this was before the days of Marxism or Maoism or Levi-Strauss or Marcuse. We were people of the immediate post-War generation, and we voted Labour for the first time after the war; this was our mild revolution. We had a great affection for British institutions: the comedies were done with affection, and I don't think we would have thought of tearing down institutions unless we had a blueprint for what we wanted to put in their place. Of course we wanted to improve them, or to use a cliché of today, to look for a more just society in the terms that we knew. The comedies were a mild protest, but not protests at anything more sinister than the regimentation of the times.”