It's called Glyn v Weston Feature Film Co,  1 Ch 261
It's all about parody, and whether it infringes copyright - in this case, it's burlesque films based on a novel, and they say that despite burlesque being "as old as Aristophanes" there are no cases where it's been held to be an infringement of copyright.
However, they also said that the novel didn't deserve the protection of the court, because it was on a "hackneyed theme" and was "grossly immoral", being a "sexual adulterous intrigue".
Here's how it was described:
The plaintiff is the authoress of the novel in debate. It is entitled "Three Weeks." First published in 1907, the book was from the point of view of notoriety fortunate enough to be condemned almost unanimously by the critics and to be banned by all the libraries. In consequence, I doubt not, of these attentions it has enjoyed a vogue denied to less daring rivals, and it has reached a sale in this*266 country and America in numerous editions, expensive and cheap, of, I was told, far over a million copies.
The book is said to be an episode in a young Englishman's life without any real beginning or end. In a sense this is a correct enough description of the novel, but the episode referred to absorbs little more than half the book - 160 pages out of a total of 319. The rest is taken up with a description of the young man's life and surroundings before the episode commenced and with a portrayal of the permanent influence upon his moral character and career which the authoress is pleased to attribute to the experience he went through during the episode in question.
The episode itself is a chance meeting at a Lucerne hotel between a beautiful lady of uncertain age and mysterious origin and the young Englishman sent by his parents on the grand tour to cure him of an unsuitable attachment at home. The meeting developed into a liaison which lasted for three weeks, after which the lady returned to the shadowy realm from which she had emerged and of which she was, as it happened, the queen. There, having given birth to a son of whom the young Englishman was the father, she was murdered by her husband, the dissolute king of the country. He in turn was assassinated by a faithful attendant of the queen's, leaving the child, the image of his handsome English father, to succeed to the throne.
In all its essentials the so-called episode is as hackneyed and commonplace a story as could well be conceived. If it is to be distinguished at all from innumerable anticipations in erotic literature, the distinction is to be found in the accessories of the tale. Mystery surrounds the lady. Of a loveliness unaffected by the passage of time, she is said to be polished, blasee, soignee. Even in a Swiss country hotel, but notably at Lucerne and Venice, she is pervaded by a luxury as sybaritic as it is incongruous: no wine can pass her lips which is not either of the deepest red or the richest gold; the roses she wears are matched in colour only by the red of her lips; the fruit with which she toys has to be out of season in order that it may be fabulously expensive. Although attended only by an elderly dignified male servant, the lady apparently carries about with her to Lucerne and Venice - if one may omit so-called mountain excursions to the Right and the Burgenstock - baggage*267 sufficient to fill an ordinary train; it is no extraordinary achievement for her dignified attendant in the space of a week-end to go from Lucerne to Venice, engage a palace on the Grand Canal, supplied with the essential convenience of a side door, and have it equipped with a retinue of Italian servants and, it would seem, an orchestra from Paris, in time to receive the lady on the following Monday travelling from Lucerne with all her baggage and apparently quite unaccompanied. These exaggerated incidents or others like them are of course quite absurd enough to be destitute of novelty in literature of the kind; but if the particular cachet of the plaintiff's novel is not to be found in this setting, then, so far as I can see, it has no cachet at all. At the best, the plaintiff has chosen a hackneyed theme for her episode, and her privilege as an authoress must be strictly confined to the method of treating it which she has adopted.
Stuffy lawyers, much? I now want to find the book and see if it's as badly written as he thought...
Godamnit, why can't law be dull? Then I wouldn't keep getting distracted!