The dignified Edinburgh House of MacPherson, famous for its hand-woven tweeds, is invaded by Mrs Angela Barrows (Constance Cummings), a slick American business efficiency expert.
Mrs Barrows impresses Robert MacPherson (Robert Morley), the mature son of the late founder, but her new methods get into the hair of old retainers, particularly Mr Martin (Peter Sellers), the staid and abstemious chief accountant.
At first, Martin sabotages Mrs Barrows’ gadgets, but she retaliates and induces Robert to sack ancient employees and make use of synthetic materials in place of hand-made tweed.
Desperate, Martin plots to liquidate Mrs Barrows while posing as a secret drinking rake. The plan backfires, yet Martin gets a far better idea, which results in Mrs. Barrows nearly being “certified.”
The House of MacPherson then returns to normal.
Peter Sellers, aping David Kossoff’s style, easily walks away with the film. Based on James Thurber’s short story The Catbird Seat.