She was a spirited young ‘It girl’ whose life was a whirl of wild nights out and reckless love affairs. He was a handsome baronet with a cast-iron reputation. On the surface their marriage was perfect, in a glossy magazine spread kind of way, but it ended in a scandalous divorce. The salacious details, splashed across newspapers, exposed obsession, revenge, debauchery and financial ruin.

What is most fascinating about the story of Sir Richard Worsley’s divorce from his adulterous wife, Lady Seymour Worsley, who lived at Harewood House, is that this is no 21st century celebrity scandal. It took place 225 years ago.

For two centuries the Worsleys’ story – culminating in one of the world’s first high-profile divorce cases – lay buried in old newspapers, pamphlets, letters and records.

Now historian Hallie Rubenhold (pictured left) has turned it into an intriguing page-turner, Lady Worsley’s Whim, offering a racy account of 18th century aristocratic life. It is filled with illicit hotel trysts, cunning revenge plots, financial downfall, foreign adventure, even a menage a trois… Seymour Dorothy Fleming, the future Lady Worsley, came to Harewood House when her mother married Yorkshire MP Edwin Lascelles. After marrying Sir Richard, Seymour had affairs with various members of the aristocracy and military.

Her ‘grand amour’ was George Bisset, an officer in the Hampshire militia, and on November 19, 1781, the pair eloped to the Royal Hotel in London. Seymour’s furious husband launched divorce proceedings, claiming £20,000 damages.

While the book is a revealing, often shocking account of life in Georgian society circles, it also raises important issues about the treatment of women during that period.

Worsley regarded his wife as little more than a possession ‘damaged’ by her affair with Bisset. He claimed his sense of honour, duty and social standing had been destroyed by a trusted friend and a wife who made a mockery of matrimonial honour.

Call it a feminist statement or call it a brutal act of revenge, but Lady Worsley certainly knew how to hit her husband where it hurt. She called her former lovers to court, setting out to prove she wasn’t worth the £20,000 Sir Richard claimed. With her reputation in tatters she had nothing left to lose, so she claimed that, as a possession, she was without value – something Worsley was well aware of.

The jury heard that Worsley practically encouraged Bisset to bed his wife. Aware of their relationship, he invited the officer to stay as a lodger. Then came one fateful balmy afternoon when Sir Richard, his wife and Bisset visited Maidstone baths, near the military base where they were staying.

What followed is deliciously described in Hallie’s prose: “The gentlemen escorted Lady Worsley to the women’s door before setting off to bathe in the men’s side. Once they had finished, they went to wait for Seymour beside the female entrance.

“Lady Worsley had hardly emerged from the bath when she heard her husband and lover. ‘Seymour!’ Sir Richard called. ‘Bisset is going to get up and look at you!’ “Suddenly the captain’s face appeared above the door. Worsley held Bisset in place (on his shoulders), permitting him to savour the spectacle of his half-naked wife as she teasingly drew on her clothing.

“The men exploded with laughter. Seymour joined them, their mirth ringing through the warm air.”

Sir Richard would later remember that day as the most regrettable of his life. When the bathhouse details came out in court, Worsley was humiliated, branded a voyeur who encouraged his wife’s lovers. Instead of £20,000 he ended up with one shilling and was turned a laughing stock by the newspapers.

As the book reveals, late 18th century gossip columns and exposes weren’t that far removed from today’s celebrity-obsessed tabloids. All that’s left of Seymour at Harewood House is a striking portrait of a young woman dressed in scarlet, clutching a horse whip (pictured right). This book brings her story to life, in deliciously racy detail.

Lasy Worsley’s Whim by Hallie Rubenhold (Chatto & Windus, £25)