Alec Guinness has one of his finest comic roles in this Ealing satirical comedy about a much patronized amateur scientist whose latest invention creates an uproar in the British textile industry. In the British manufacturing country of Northern England, factory owner Michael Corland (Michael Gough) is showing competitor Alan Bimley (Cecil Parker) around his plant, hoping to borrow some money and marry off his daughter Daphne (Joan Greenwood). They come upon a curious contraption that turns out to be an experiment by employee Sidney Stratton (Alec Guinness). Being a lower class worker, Sidney is summarily fired from his job. Sidney ends up working at Bimley's factory, where he is befriended by militant worker Bertha (Vida Hope). Daphne spots Sidney at the factory and he explains to her the results of his experiment -- a material that is indestructible and impervious to dirt. Bimley discovers this project and throws Sidney out. But Daphne, impressed by his experiments, funds Sidney, installing him in his own laboratory. After a few false starts, Sidney develops a pure white material that can't be dirtied or ruined. But it seems Sidney's invention is too brilliant and effective; if a material is marketed that will last forever, textile mills will go out of business and workers will lose their jobs. Suddenly, poor, luckless Sidney has both management and labor banding together to combat his new invention.
~ Paul Brenner, All Movie Guide