Channel 4 (UK) Documentaries - 2011x27 - Britain's Greatest Codebreaker- Followmy.tv

The story of the Queen Mother's nieces Nerissa and Katherine Bowes-Lyon, who were born with learning difficulties more than 80 years ago and spent most of their lives in an institution. In 1963 Burke's Peerage wrongly stated that the two had died, but Nerissa survived until 1986 and Katherine is still alive, although there is no known record of them ever having been visited by any member of the Bowes-Lyon or royal families - despite the Queen Mother being a patron of Mencap.