Margaret, the duchess, was a woman who was adored for her beauty and style from her time at school in New York, but later became better known for her infidelity and promiscuity.
So, who was the real Duchess of Argyll - and what is the story behind A Very British Scandal? This is what you need to know.
Who was Margaret, Duchess of Argyll?
The duchess was born Ethel Margaret Whigham in December 1912 in Newton Mearns, Renfrewshire.
She was the only child of Helen Mann Hannay and George Hay Whigham, a Scottish millionaire who chaired a multi-billion dollar technology company in the US.
She grew up in New York, where she was educated at the prestigious Hewitt school.
As a young girl, she was taken to see a psychiatrist who diagnosed her only as lacking a sense of humour.
She also developed a stammer, and was treated unsuccessfully by Lionel Logue, speech therapist to King George VI.
During her time at high school, she was admired by many and found herself in various relationships as a teenager.
Her admirers included Prince Aly Khan, millionaire aviator Glen Kidston and publishing heir Max Aitken, but her first true love was David Niven, who went on to become a great actor and novelist.
Margaret’s tumultuous romances began when she returned to England in 1928.
18-year-old Niven and Margaret, 15, engaged in a sexual relationship which resulted in pregnancy.
She was rushed to a private care facility by her father, where a termination of the pregnancy took place. Despite her parents breaking off their relationship, Margaret continued to admire Niven until his death in 1983, she was a VIP at his London memorial service.
She had been presented at Queen Charlotte’s ball in 1930, aged 18, as the most beautiful debutante (girl matured to the age of marriage) to a room full of aristocracy, royalty and upper classes.
Throughout her life, she became a socialite best known for her glamorous sense of style and dressed by Hartnell, Victor Stiebel and Angéle Delanghe in London.
Who was the Duchess of Argyll married to?
Margaret went on to marry her first husband, American businessman Charles Sweeny, after a failed engagement to the 7th Earl of Warwick.
The Sweeny’s married in February 1933 after Margaret converted to the Roman Catholic church.
In the run up to her wedding, there had been so much publicity surrounding her Norman Hartnell wedding dress, that the traffic in Knightsbridge was blocked for three hours as onlookers revelled in her beauty.
They remained married until 1947, welcoming three children together - a daughter, who was stillborn at eight months in late 1933; another daughter, Frances Helen was born in 1937, and a son, Brian Charles born in 1940.
Prior to the birth of her first daughter, she also suffered the loss of eight children to miscarriages.
In 1947 she divorced Sweeney, she later recalled “All Charlie wanted in a wife was a pretty, brainless doll,” while he claimed she “changed her totally” after she fell down a lift shaft in 1943.
Following their divorce, she went on to have several short-lived romances, including one with Theodore Rousseau, curator of the Metropolitan Museum of Art, who she described as "highly intelligent, witty and self-confident to the point of arrogance", but not “step father material”.
When did the Duke and Duchess of Argyll marry?
In March 1951, she wed the 11th Duke of Argyll, Ian Douglas Campbell. She was his third wife.
Speaking of her marriage to the duke, she described his attraction to her: “I had wealth, I had good looks. As a young woman I had been constantly photographed, written about, flattered, admired, included in the Ten Best-Dressed Women in the World list, and mentioned by Cole Porter in the words of his hit song ‘You’re the Top’.
“The top was what I was supposed to be. I had become a duchess and mistress of a historic castle. My daughter had married a duke. Life was apparently roses all the way.”
From the outset the marriage was troubled and littered with distrust and accusations of infidelity.
While he wiretapped her car, she wrote false letters claiming that his sons to his second wife were not biologically his and attempted to acquire a baby boy to claim as their son, in order to be the mother of the heir to his fortune.
What happened during the duke and duchess’ divorce?
In 1963, the Duke filed for a divorce from his wife after fearing she had been cheating.
While she was in New York, he hired a locksmith to break into a cabinet in their Mayfair home, 48 Upper Grosvenor Street.
Inside, he found photos of the duchess naked other than her signature three-strand pearl necklace.
In their divorce case, he accused her of infidelity and cited Polaroid pictures from the cabinet in which one showed her performing oral sex on a man whose head had been cropped from the pictures. He became infamous as the “headless man".
The man in question was believed to be the Minister of Defence Duncan Sandys, the son-in-law of Winston Churchill.
Throughout the divorce proceedings, the Duke provided a list of 88 men whom he believed his wife had been engaging in extramarital affairs with. The list included government officials, three members of the royal family and several actors.
Many of the men are thought not to have been her sexual partners, tens of those named were gay but she did not provide this as evidence in court at the time as homosexuality was illegal in the UK.
The judge described Margaret as having indulged in "disgusting sexual activities", and narrowed down the identification of the headless man to five potential “suspects”.
It has since been reported that the suspect was privately confirmed as American actor and producer Douglas Mary Lee Epling. He denied the accusation fervently.
The judge determined Margaret "was a completely promiscuous woman whose sexual appetite could only be satisfied with a number of men,”
"Her attitude to the sanctity of marriage was what moderns would call ‘enlightened’ but which in plain language was wholly immoral,” he added.
It has since been claimed that there were two headless men, one being Fairbanks and the other Duncan Sandys.
Sandys was identified as a potential lover when the Duchess’s statement read "the only Polaroid camera in the country at that time had been lent to the Ministry of Defence".
Did she remarry?
Despite the many comments about her love affairs and promiscuity, Margaret did not remarry.
For the three decades until her death in 1993, she continued to live a privileged life but without the funds to do so.
In 1975, she released a memoir titled ‘Forget Not’, which was critically slated for name dropping.
She eventually had to leave Upper Grosvenor Street after her attempts to offer public tours around the property failed to bring in enough money to pay off her debts.
She moved to an apartment in the Grosvenor Hotel in 1978 but was evicted in 1990 for failing to pay hotel bills.
Her family and first husband rallied around and put her up in an apartment, until she was placed in a nursing home in Pimlico, London.
Margaret died in penury in 1993 after a fall in the nursing home, her children buried her with their father, Charles Sweeny, in Brookwood Cemetery in Woking, Surrey.