A Royal Cover-Up?

Katherine Bowes-Lyon was the daughter of John Herbert Bowes-Lyon and his wife Fenella (née Hepburn-Stuart-Forbes-Trefusis). As John was the brother of Elizabeth Bowes-Lyon, the Queen Mother, she and her sister Nerissa were first cousins of the British Queen Elizabeth II, sharing one pair of grandparents, Claude Bowes-Lyon, 14th Earl of Strathmore and Kinghorne and Nina Bowes-Lyon, Countess of Strathmore and Kinghorne.
Both Nerissa and Katherine had been placed in Earlswood Hospital for the mentally disabled in 1941. Although Nerissa died in 1986, and Katherine in 2014, both had been listed in Burke's Peerage as being dead since the 1963 edition. Suggestions of a royal cover-up were rejected in the press by Lord Clinton, who thought that his aunt Fenella (the mother of the two daughters) had completed the form for Burke's Peerage incorrectly due to 'vagueness'. However, Burke's Peerage included specific dates of death for both sisters.

According to a 2011 television documentary about the sisters, "throughout their time at the hospital, there is no known record that the sisters were ever visited by any member of the Bowes-Lyon or royal families, despite their aunt, the Queen Mother, being a Patron of MENCAP" (the charity for people with a learning disability). Nurses interviewed on the documentary said that, to their knowledge, the family never even sent the sisters a birthday or Christmas gift or card.
When Nerissa died in 1986, none of her family attended the funeral. She was buried at Redhill Cemetery. Her grave was only marked with plastic tags and a serial number until her existence was revealed in the media, after which the family added a proper gravestone.
Three other mentally disabled cousins also lived in Earlswood Hospital. Harriet Hepburn-Stuart-Forbes-Trefusis (1887–1958), sister of Nerissa and Katherine's mother Fenella, married Major Henry Nevile Fane, and 3 of their 7 children lived in Earlswood Hospital: Idonea Elizabeth Fane (1912–2002), Rosemary Jean Fane (1914–1972), and Ethelreda Flavia Fane (1922–1996).[15] Prof. David Danks, then director of the Murdoch Institute, thought that a genetic disease may have killed male members of the family in early childhood. In 1996 the surviving cousins were moved to Ketwin House care home in Surrey, and when it closed in 2001, they were moved to another care home in Surrey.