Threesomes with servants, accusations of STDs and a jury ordered to peek through an aristocrat's keyhole to check what the butler REALLY saw - the incredible salacious tales from Britain's first divorce court

What an extraordinary sight it must have been the day Belle Bilton, a 'much-photographed music hall artiste', stepped out from the Royal Courts of Justice. Lord Clancarty, her father-in-law, had done everything in his power to get rid of her, yet here she was, triumphant.

The singer had just been found not guilty of adultery in London's divorce court. To Clancarty's horror, and despite his best efforts, she was still married to his son, Viscount Dunlo.

Traffic came to a standstill on the Strand as hundreds gathered to see her: men clambered on top of the omnibus just to catch a glimpse. Hats and handkerchiefs were waved and cheers of 'Bravo, Lady Dunlo!' rang out.

It was the culmination of six days of jaw-dropping evidence that held outwardly staid Victorian society spellbound in July 1889 as Belle's rackety past was raked over.

Hers was one of many cases pored over at the Royal Courts of Justice – newly minted to hear divorce trials – that made headlines day after day in a heady mix of celebrity, salaciousness and intrigue. And they are, as social historian Ruth Derham shows in her new book, Decadent Divorce: Scandal And Sensation In Victorian England, a fascinating insight into how British society was changing.

The Royal Courts of Justice – newly minted to hear divorce trials – made headlines day after day in a heady mix of celebrity, salaciousness and intrigue

Gertrude, Lady Colin Campbell, is said to have had a quartet of illicit suitors

Indeed, the fortunes of supposedly disreputable Belle Bilton spun on a sixpence when she gave a stellar turn in the witness box.

Belle – one half of the Sisters Bilton, a duo whose cultivated innocence on stage was encapsulated in the chorus 'We're fresh, fresh as the morning, sweeter than new mown hay' – had met the young Viscount Dunlo, just 20 years old, at London's Corinthian Club in April 1889. The club, just off St James's Square, offered its clientele 'fun in the early hours' and 'a delightful absence of ceremony with respect to both sexes'.

Dunlo was instantly smitten and Belle, a couple of years his senior, equally so. Three months later, they married in secret. The first the 4th Earl Clancarty knew of it was a report in the Pall Mall Gazette. To describe Clancarty's reaction as volcanic is an understatement. He was already afraid his son was falling into bad company but the thought of a showgirl parading around as Lady Dunlo was intolerable. He was determined to put a stop to it.

Dunlo crumbled in the face of his father's wrath and agreed to abandon his wife: he was sent to Australia, while Clancarty instructed a solicitor to have Belle's every move watched by detectives. Under the law, a man could petition to divorce his wife for one simple act of adultery. Clancarty soon heard, to his satisfaction, that Belle was 'daily in the company' of a Mr Isidor Wertheimer.

Convinced they were having an affair, he persuaded Dunlo to sue for divorce. But the ensuing trial spectacularly backfired.

Before a packed court, the sad story of Belle's life unfolded. The daughter of a staff sergeant in the Royal Engineers, she had taken to the stage aged 14, and in 1887, just before she turned 21, had met an older, married man, by whom she had become pregnant.

Seemingly respectable, he turned out to be a thoroughly bad lot and was convicted soon afterwards of being party to misappropriating £50,000 – nearly £5million in today's money – and jailed. Wertheimer was Belle's saviour. They met first at the Trocadero Club and she confessed to him she was pregnant. He took a house for her in Maidenhead, where she lived under his protection until her baby was born (Belle named him Isidor, after her benefactor, but what happened to him is unclear). She later met Dunlo but kept up her acquaintance with Wertheimer.

Belle Bilton, the showgirl who married an earl, was found not guilty of adultery, despite her father-in-law's best efforts

Lady Clancarty with his wife, the former 'music hall artiste' Belle Bilton

Charles Dilke, a Liberal MP tipped to take over the party leadership from Gladstone, had his affair rumbled after poison pen letters were sent to his lover's husband

No one disputed that Wertheimer was in love with Belle but the jury believed him when he said that he had only once so much as put his arm around her waist 'much to her annoyance'. They were adamant they had not had any romantic encounter and, though grateful for his kindness, she kept him at arm's length. The charm that had won Belle her following on stage was put to full use in the witness box. The press marvelled at her pretty gown 'with corrugated flummery on the arms'. Her dignified manner held the court in thrall. When she was asked why she'd allowed Wertheimer to 'dangle' at her heels she replied: 'My husband did not look after me, so what was I to do?'

The jury took just 15 minutes to find Belle not guilty and the petition was dismissed. Having entered court as a showgirl, Belle left as a star. The Trocadero, London Pavilion and Royal Theatre vied to sign her at £100 (£11,000 in today's money) a night.

That people took Belle's side – rather than her aristocratic father-in-law's – indicates how society was changing. The arrogance, entitlement, faults and foibles of the aristocracy exposed in such divorce cases eroded respect among working class newspaper readers, eager for scandal.

The sating of their appetites had been a long time coming. Before, divorce had been possible but rare, as an Act of Parliament was required. But in 1857, a new law came into force allowing couples to divorce under strict conditions – most usually proof of adultery – and Britain's first dedicated divorce court opened its doors in 1883. And it soon became a forum in which couples, mostly the aristocracy and the very wealthy who could afford the top lawyers, aired their dirty linen in public.

Couples unhappy enough to risk social ostracism by divorcing accused each other of cruelty, infidelity and sexual deviancy. The more lurid details were gleefully reported by Fleet Street's eager press, with much of the evidence coming from servants claiming to have seen 'goings-on' through bedroom keyholes. There was high drama and laughs aplenty as reputations and careers went up in smoke, but the workings of the divorce court tell us more than just what it takes to destroy a marriage – they shone a light on shifting attitudes in society. The 'double standard' inherent in the law, for instance, caused outrage. Today, a consenting couple can opt for a DIY divorce online for a £593 fee, but in the 1800s a petitioner had to show fault – and the system was very much weighted in men's favour.

A husband could divorce his wife for one, simple act of adultery – a 'fair suspicion' was enough. A woman could only divorce her husband for 'aggravated adultery'. He had not only to be unfaithful, the infidelity had to be accompanied by cruelty, desertion, bigamy or incest. In all but exceptional circumstances, the husband had to name the man who had 'defiled' his wife and could claim damages from him. A wife had no such claim on her husband's alleged mistress.

Divorce was still rare and it was thought that the open invitation to the Press to report matters in the court would act as a deterrent. So the authorities were shocked to see petitions 'flood' in at a rate of 300 a year, more than half of them filed by women.

The veil of Victorian respectability was pulled back in 1886 with two great causes celebres, described by the author George Moore as notable for their 'animal uncleanliness, foul and sardonic vice or stupendous revelations of mean hatreds and meaner vanity'. The cast included aristocrats, the nouveau riche, professionals and politicians in the most compromising situations.

The first concerned Donald Crawford, secretary to the Scottish Lord Advocate and soon-to-be MP for Lanarkshire North-East. At 44, he had married 18-year-old Virginia Smith, daughter of the MP for Tyneside North-East, a wealthy shipbuilder. Virginia did not love him – the match had been made by her parents, who considered her wilful and in need of a firm hand. Virginia was desperately unhappy. In London, during the parliamentary term, she spent as much time as possible away from home, allegedly doing charity work in the East End.

Crawford began to receive poison pen letters accusing his wife of affairs. At first, he burnt them but, eventually, overcome with suspicion, Crawford forced a confession from her: 'The real man with whom I have been guilty… is Charles Dilke,' she said.

This was astounding. Dilke was a Liberal MP, tipped to take over the party leadership from Gladstone, and therefore likely to be the next Liberal prime minister.

Even more surprisingly, Dilke had already had an affair with Virginia's mother, an art collector and society hostess. His brother was married to one of Virginia's sisters. So matters were already complicated even before Crawford sued for divorce.

Virginia said Dilke had visited her six months after her marriage, spoken seductively, and kissed her. During the next parliamentary session, in 1882, they first had sex. Their affair lasted for more than two years: in February 1883 they had two whole nights together when she came up to town before Crawford returned. She got home just in time to bathe and dress before he arrived.

Then, the bombshell: he had coerced her into a menage-a-trois. She blurted out: 'He made me go to bed with Fanny' (one of Dilke's servants and alleged mistresses).

Crawford petitioned the court, naming Dilke as co-respondent. The Pall Mall Gazette reported events as they unfolded under the headline 'The Great Social Scandal'. More about what Virginia had to say about the threesome came out in court.

'I did not like it at first but I did so because he wished it,' she had told her husband. 'I would have stood on my head in the street if he had told me to do so. He used to come to bed beside us. He taught me every French vice. He taught me all I know. He used to say that I know more than most women of 30. He said he took me first because I was so like my mother.'

For the masses, this was top-class entertainment. But what happened next turned the case from a hiccup in the career of a politician to the means of its destruction. Dilke's lawyer declared that, as the prosecution's case relied solely on Virginia's confession, there was no case for Dilke to answer. The Judge, Mr Justice Butt, agreed. He would give Crawford his divorce but dismiss Dilke from the case.

The press was astonished: the judge had effectively ruled that Virginia had committed adultery with Dilke but Dilke had not committed adultery with her! The fact that Butt had been a Liberal MP before he was raised to the bench and was an old friend of Dilke's gave the impression that it had all been 'squared' beforehand.

Dilke chose not to speak in his own defence. The Pall Mall Gazette speculated on how bad Dilke's other 'indiscretions' must be to have kept him out of the witness box. The press continued asking awkward questions for weeks – until the Queen's Proctor, appointed to prevent miscarriages of justice in divorce suits, stepped in. Dilke had encouraged this, believing that his best shot lay in being exonerated again.

It was a disastrous misjudgment. This time, Dilke denied adultery. His footmen denied having let Virginia into the house; his servant Sarah denied getting Fanny into the house and up to Dilke's bedroom.

But Virginia's cool, shameless account of every detail – how she, Dilke and Fanny had gone to bed together, how she had lied to her husband – was compelling.

A respectable young lady would never blacken her name with false testimony, the Victorians believed, so Dilke must be a liar. There were calls for him to be prosecuted for perjury. He escaped that fate but had to leave Parliament for a time and never again rose above being a backbencher.

And just four months after the divorce court doors closed on Dilke, the papers' presses were at it again, churning out copious reports of the next sensation.

When Lord Colin Campbell, son of the Duke of Argyll, encountered Gertrude Blood, it was love at first sight. Three days after they met, they got engaged. But three months into their marriage the idyll was shattered. Campbell, MP for Argyllshire, infected his wife with a sexually transmitted disease.

Gertrude, now Lady Colin Campbell, applied for a judicial separation. Campbell argued that he had followed doctors' advice and that his wife had been aware of his condition. He lost and was ordered to pay her alimony of £225 (£25,000 today) a year.

Two years later, in 1886, both parties sued for divorce. 'Happy lawyers!' wrote the South London Chronicle: it promised to be 'a great entanglement!' And so it was. Campbell accused his wife of adultery with four men: Captain Eyre Massey Shaw, Chief of the Metropolitan Fire Brigade; Brigadier General Sir William Francis Butler, serving in the Sudan; Dr Thomas Bird, her physician; and George Charles Spencer-Churchill, Marquess of Blandford at the time of the alleged adultery and Duke of Marlborough when it came to court.

An illustration of a court scene captures the sense of excitement as a witness makes a lurid revelation

Couples unhappy enough to risk social ostracism by divorcing accused each other of cruelty, infidelity and sexual deviancy

 By comparison, the allegation in Gertrude's petition was trivial: one act of adultery with a maid, Amelia Watson. Campbell claimed it was only after he had accused his wife of adultery that she and her lawyer concocted the charge of venereal infection to distract from her guilt.

His case began with a flourish: a doctor had examined Amelia and pronounced her a virgin. 'Sensation!' cried the press. But that did not preclude a guilty verdict if there had been 'overfamiliarity'. Gertrude's cousin, Frances, claimed to have heard Campbell tell Amelia she had 'very pretty hair' which he liked to take down and play with. She had spied on the pair one evening in and said she saw Campbell 'sitting on the edge of the bed in his nightshirt with his arms around [Amelia's] neck and she leaning against his knee'.

James O'Neill, the Campbells' butler, gave evidence against Lady Campbell. He said when Gertrude was at home he had frequently answered the door to Shaw and Marlborough and on one occasion, when he took tea up to the drawing-room, he found the door locked. When he returned ten minutes later it was unlocked, the sofa and cushions were disarranged and Gertrude's face flushed.

On another occasion, he heard noises coming from the dining room and peered through the keyhole. O'Neill said he saw Gertrude lying on the dining room floor with Shaw on top of her. The couple were 'in a position that would admit of but one construction'.

'Sensation!' once again.

Gertrude's lawyer tried to undo O'Neill by questioning his ability to hold a tea-tray balanced on his knee with one hand as he crouched to look through the keyhole. So crucial was this point that the jury ended up travelling across town to look at the keyhole themselves.

Campbell was said to have become 'suspicious, morbid and jealous' through unwisely listening to servants' gossip. It was suggested he had included Gertrude's doctor in the list of lovers to avoid paying his bill. The jury found both parties not guilty – so the petitions were denied and they were obliged to stay married. At 18 days, the trial was the longest in the divorce court's history and cost £18,000 (nearly £2million today). Campbell was ruined in every respect. The following year he went bankrupt. While Gertrude embarked on a career as a journalist and playwright, her husband fled to India.

And what of Belle Bilton, the showgirl who took on an earl? She and Dunlo were reconciled but Lord Clancarty hadn't finished. Less than two weeks after the trial, he rewrote his will. He could do nothing to prevent his son inheriting his title and his 27,000-acre estate in Ireland but he cut him from his personal estate, valued at more than £50,000.

In the fullness of time Belle did become a countess but, sadly, it was not to be a happy experience. Her marriage may have started in a blaze of fervour but she allegedly struggled to adapt to her new role. Despite her triumph in court, she had borne an illegitimate child by a convicted criminal. She was never really accepted by Ireland's ruling class.

More used to London's glittering theatreland, she was bored by life at the vast but remote family estate in Galway. Ample opportunity then, to reflect on the old adage – marry in haste, repent at leisure.

Decadent Divorce: Scandal And Sensation In Victorian England by Ruth Derham (Amberley, £22.99) is published May 15. To order a copy for £20.69 (offer valid to 25/05/24; UK P&P free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937.