The Crown fact-check: Did the Queen and Margaret really have two secret cousins with developmental disabilities?

Who plays Katherine and Nerissa in The Crown?

The role of Katherine is played by Trudie Emery, while her older sister Nerissa is played by Pauline Hendrickson.

Another actor in the episode is John McCormack, who plays one of the nurses; he runs a filmmaking-focused day centre "where people with learning disabilities gain new skills whilst having fun with their friends," including some of the cast of this episode of The Crown.

Who were Katherine and Nerissa Bowes-Lyon?

Princess Margaret actor Helena Bonham Carter wasn't initially sure if the existence of Katherine and Nerissa was fact or fiction, explaining how she'd asked The Crown's showrunner for clarification: "I hadn’t heard this story before and I immediately said to Peter Morgan, 'Is this you or history?'"

But Katherine and Nerissa Bowes-Lyon were very much real people, and – just as we see in The Crown – they were first cousins to Queen Elizabeth II and her sister Princess Margaret. They were put in care and kept secret from the public.

Nerissa (born in 1919) and Katherine (1926) were the daughters of John Bowes-Lyon and his wife Fenella. The couple had five daughters in total, though one did not survive infancy.

Although he didn't live to see his niece take the throne, John was Queen Elizabeth II's uncle; John's sister was Elizabeth Bowes-Lyon, known to us as the Queen Mother.

Both Katherine and Nerissa were born with developmental disabilities. They seem to have been raised at home, but in 1941 – aged 15 and 22 respectively – they were quietly placed in the Royal Earlswood hospital for people with developmental disabilities.

The Guardian writes that they were placed there by their parents and "had, to all intents and purposes, been abandoned. There is no record of either woman ever receiving a family visit".

However, their father John was already dead by this point (having passed away in 1930); it seems they were put in the hospital by their mother Fenella, who continued to visit them until her own death in 1966, according to Maclean's. Fenella's granddaughter also said other members of the family had often visited over the years.

The Bowes-Lyon sisters were kept company by even more of their relatives: another group of sisters called Idonea, Ethelreda and Rosemary Fane. All five were placed in the institution on the same day in the middle of the Second World War. The Fane sisters, however, were not blood relations of the Queen; they were Fenella's sister's children.

Nerissa died in 1986 at the age of 66, and was buried in what some have called a "pauper's grave" and others have called a "humble plot" in Redhill. The spot was marked with a small plastic marker.

It was Nerissa's death which alerted the press to the fact of her life, and in 1987 the story broke – The Sun ran the headline "QUEEN'S COUSIN LOCKED IN MADHOUSE" alongside a picture of Katherine.

The sisters were reported to have a genetic disorder which did not affect the Queen or any heirs to the throne. It seems to have passed through the maternal grandfather, Baron Clinton. Genealogist Hugh Peskett said that the "the great relief is that the genes are obviously in the Clinton family and not in the royal family".

The Royal Earlswood Hospital closed in 1997, as services shifted towards a "care in the community" programme, and Katherine was moved to an NHS care home called Ketwin House alongside her surviving cousin Idonea Fane.

Idonea and Katherine both had a mental age of around six, and were said to be inseparable; but they were, in fact, separated when Idonea was sent to another care home shortly before her death in 2002. Katherine lived on until 2014.

Did Burke's Peerage list the cousins as dead?

Yes. Burke's Peerage is a two-century-old reference book to the nation's royals and aristocracy. It declared that Nerissa had died in 1940, and later that Katherine had died in 1961. But why?

Fenella's granddaughter Lady Elizabeth Anson issued a statement in 1987 saying "there was no attempt at a cover-up", saying that her late grandmother Fenella "a very vague person who often didn’t fill out the forms that Burke’s Peerage sent her, either properly or completely.”

So it seems that Fenella, intentionally or not, had led Burke's Peerage to believe that her daughters had both died – 21 years apart.

The then-editor of Burke's Peerage, Harold Brooks-Baker, said he was stunned to discover the error, declaring: "If this is what the Bowes-Lyon family told us, then we would have included it in the book... It is not normal to doubt the word of members of the royal family."

Why were the Queen's cousins put in care and kept secret?

The Crown puts forward the argument that it was to save the Royal Family from questions about hereditary mental illness.

Helena Bonham Carter says: "In The Crown scripts, Peter [Morgan] has the Queen Mother put across her side of the argument... people will be shocked of course but Marion [Bailey, who plays the Queen Mother] has some amazing scenes where she says you can’t take things out of time.

"Of course we will all rush to judge, but the sad thing is the Royal Family were not the only people to lock up or put away people who were disabled. It was in the 1940s, it was during the war and their mother was overwhelmed. You could argue that they had the care that they needed... At that time there was a huge amount of shame and lack of knowledge associated with brain damage or disability and in a religious sense it was associated with sin.

"The Queen Mother’s explanation for the families' actions [in The Crown] is that it was a hereditary principle. They are in such a perilous position that any sniff of imperfection has to be covered up and dealt with. It seems to be The Crown throughout the series, as in life, they are always having to justify their position and keep hold of their jobs."

Were they 'discovered' by Princess Margaret?

In The Crown, Princess Margaret uncovers the fact that Katherine and Nerissa are still alive in the mid-1980s after receiving some information from her therapist. Refusing to believe what she reads in Burke's Peerage, she enlists priest-in-training Derek "Dazzle" Jennings to visit the hospital and find out if her cousins are patients there; after he talks to them in-person, she confronts her own mother who defends the family's decision to hide the girls away.

But in reality, Princess Margaret does not seem to have played any part in 'discovering' her cousins. And, contrary to the story we see in The Crown, the Queen Mother (who was a patron of the learning disability charity Mencap) does not seem to have been aware of what happened to her nieces until 1982, when the hospital's "Friends" group wrote to her.

Until then, she had apparently thought her nieces were dead; after finding out, she sent them money which was used to buy candy and toys for their birthdays and for Christmas.

But the entry in Burke's Peerage was not corrected until the story broke in the newspapers five years later.

And after it did break, a spokesperson for Buckingham Palace said that the Queen was aware of Katherine and Nerissa but that "we have no comment about it at all. It is a matter for the Bowes-Lyon family".

Did Princess Margaret worry she had inherited mental illness?

In the episode, Princess Margaret experiences mental distress – and after hearing rumours about her cousins and their disability, she wonders about a possible connection.

But while it's hard to say for certain, in real life Margaret probably wasn't too worried about the developmental condition affecting her cousins as it had been present since their birth.

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However, she may have paid more attention to the spectre of her 3rd great grandfather, King George III, who famously went "mad".

Here's a sliver of an anecdote from Craig Brown's book 'Ma'am Darling', taken from December 1991: "Friends take Princess Margaret to see The Madness of George III by Alan Bennett. In the interval, she smokes and sips nervously from a glass of Famous Grouse. 'Do you think it's hereditary?' she asks."

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