Muriel Diana, the elder child of Montgomery Reader Harris (born 1887) and his wife, Frances Mabel (née Wilmot Wilkinson), returned to England at the age of two, but lost her mother to meningitis almost immediately, and as her father remained in the Far East, she was brought up by an aunt in London.
During the war she was evacuated with a group of pupils from Sherborne to Branksome Hall School in Toronto, Ontario, Canada.
According to an obituary, "Those who were pupils during her headship grew up in an atmosphere in which it was assumed that everyone had something of value to give, a better nature to be appealed to, and a duty to the community in which she lived.
She was at various times a member of Dorset Education Committee, the Independent Television Authority, the councils of the National Youth Orchestra and the Outward Bound Trust, the Church Missionary Society, where as its first woman president[5] she brought it to espouse the 1980 Brandt Report on bridging the North-South divide, and Christian Aid, where she was also chairman in 1978–1983.
[citation needed] Reader Harris was an active member of the Church of England and a keen advocate of the ordination of women.
After retiring at the age of 63, she took on a bewildering array of offices in Church, educational and charitable organizations, including Chairmanship of Christian Aid."