Based on the true story of Gavin Maxwell, who bought an otter in London and brought it back to his home in Scotland, only to discover that this was a subspecies of otter not yet recorded. Maxwell gave his name to the new sub species' title: Lutrogale perspicillata maxwelli.
The title of the movie and autobiographical book is taken from a poem by Kathleen Raine, who had considered the book's author, Gavin Maxwell, the love of her life. In reality Maxwell was gay, a fact that did not become known to the public until 1976 when his friend Richard Frere published a memoir entitled "Maxwell's Ghost".
Leads Bill Travers and Virginia McKenna reunite from the hit movie Born Free (1966), a fact which was emphasised in the advertising for this film.
In the opening scene of a busy London street, a Lady Godiva-like character is briefly scene riding a horse in an urban area. She is not naked, but is wearing a flesh-coloured body-stocking/bathing-suit.