While Heather Mills, for example, saw details of her personal life raked over in what must be one of the most acrimonious court hearings of recent times, she had nothing on Lady Worsley.

Life had begun ordinarily enough for the step-daughter of Lord Harewood, Edwin Lascelles, but her society marriage to Sir Richard Worsley in the Yorkshire estate's All Saints church in 1775 was about as near as she would come to conforming with the protocols of polite society.

"She was what they call a colourful character," says Hallie Rubenhold, an art history graduate of Leeds University, who has chronicled Lady Worsley's life and the scandal which was to overshadow it for the first time. "Lady Worsley was a spirited young heiress and Sir Richard was a handsome baronet with a promising career in government. The marriage had the makings of a fairytale, but ended as one of the most highly publicised divorces in history. While studying art history I had come across the famous portrait of Lady Worsley by Joshua Reynolds.

"Her story had always stuck at the back of my mind and I just thought I really must go back and dig a little deeper to what happened all those years ago."

Shortly after her wedding to Sir Richard, the couple moved to the Isle of Wight where Lady Worsley, who had already earned a reputation for being free with her affections, began an affair with a local militia captain, George Bisset. In November 1781, the lovers decided to run away to London in the full knowledge their indiscretion would set Sir Richard on the path to the most public revenge.

"He launched what was known then as criminal conversation action," says Hallie. "Basically it involved proving that Bisset had reduced the worth of his wife, and Sir Richard, so aggrieved at what had happened, demanded £20,000 in compensation, an astronomical sum at the time."

The subsequent trial left all parties nursing their egos. In order to prove Lady Worsley'sworth was tarnished long before the arrival of Bisset, her various other lovers were called to give evidence. Others testified that Sir Richard had actively encouraged Bisset to peer at his naked wife through a bathhouse window. The court proceedings gave the scandal sheets and gossip columnists much to write about, but as Hallie discovered when she began her research, a large amount of personal correspondence relating to the affair was destroyed.

"When I arrived on the Isle of Wight I asked everyone I met whether they knew about Lady Worsley and
the scandal which had enveloped her," she says. "But the story seemed to have been buried by the passage of time. The Georgians were prolific letter writers, but those which related to some family scandal were often destroyed at a later date in an attempt to restore reputations. In a case like this it is a real loss. "It was quite hard going finding exactly what had gone on, but bit by bit it became clear that this was a darker and more twisted story than I had ever dreamt of. The Eureka moment came when I realised depositions of the trial had survived. They are 300 pages of the most damning and intriguing evidence I have ever read."

Servants, friends and family were all called to give evidence and the tawdry picture of the threesome kept the masses entertained for months. Captain Bisset was eventually found guilty. However, during the trial it emerged Sir Richard had encouraged his former friend to view his naked wife while bathing, and he was awarded just one shilling in compensation. "Sir Richard's reputation was in tatters, but Lady Worsley continued to defy social convention," says Hallie. "She never once betrayed a hint of regret and showed no intention of withdrawing from fashionable London life.

"She took up with a group of aristocratic divorcees who because of their high birth could slip between the drawing room and a shadowy underworld. Her behaviour was completely erratic, showing signs of what would now be diagnosed as manic depression. Hers is a fascinating story but one tinged with sadness."

Lady Worsley's Whim: An Eighteenth Century Tale of Sex, Scandal and Divorce, published by Chatto and Windus, priced £25 is out next month.

Hallie will launch the book with a talk on Lady Worsley at Harewood House on Nov 15. Tickets, which cost £14.50, are available by calling 0113 218 1000.