Virginia Crawford, 22, announced to her husband - who later repeated the claims in the divorce court - that she and Dilke had had a long sexual liaison, meeting at his home in Chelsea and in various houses of assignation. "He taught me every French vice," she said. "He used to say that I knew more than most women of 30."
Most damningly, she declared that during their love-making Dilke had persuaded a young servant girl, Fanny Grey, to join them in bed. Virginia said she had resisted this but the MP, whom she portrayed as a sexual monster, forced her to co-operate.
Dilke was mocked in the press and the music halls and was shunned in society. After an unsuccessful attempt to clear his name he quit politics and, although he later returned to the Commons, he was never again a Cabinet minister.
The story does not end there. In the words of his latest biographer, David Nicholls: "Historians who have studied the divorce case in any depth have concluded that Dilke was in all probability innocent of any adulterous relationship with Mrs Crawford."
This is not to say that the Liberal politician was pure as driven snow. Aged 42 at the time and single, he was known as a ladies' man and among his previous paramours was Virginia's mother.
But Virginia also had a sexual track record. The daughter of a Tyneside shipbuilder, at the age of 18 she had been forced against her will to marry Donald Crawford, a man twice her age. With a married sister, Helen, she then set about finding consolation with lovers, particularly among the medical students at St George's Hospital.
Both she and Helen also had affairs with an army captain, Henry Forster, whom they met frequently at a brothel in Knightsbridge, and Dilke's friends later produced evidence that the two young women shared the attentions of several men, possibly in the same bed at the same time.
If Dilke was framed, why? Various theories have circulated. Politically, he was important and controversial and many people, Liberal and Tory, were glad to see him fall. Queen Victoria was particularly amused, as he was the leading republican of his time.
But Dr Nicholls, in his recent Sir Charles Dilke, The Lost Prime Minister, argues that none of the political conspiracy theories stand up to scrutiny. Instead he suggests that Dilke was the victim of a more domestic plot.
Virginia was desperate for a divorce, but in the hope of avoiding publicity about her sexual past and of protecting her true lover, Forster, she decided to name some other, innocent man. Her choice fell on Dilke because of his past relationship with her mother and because she was encouraged by a friend, Christina Rogerson, who felt she had been jilted in love by Dilke.
The MP thus found himself with the almost impossible task of demonstrating in court that he had not had an affair with Virginia. Even though Fanny Grey declared there was no truth in the three-in-a-bed charge, Dilke was unable to prove the negative. Although his political career was thrown off course, things could have been worse. A rich man already, he married a wealthy widow at the height of his troubles and lived on until 1911.
Virginia, after her divorce, went on to lead a colourful life. She became a writer on literary and religious matters, was a Labour councillor in London for 14 years and campaigned so vigorously against fascism that Mussolini blacklisted her. She died in 1948.Reuse content