From the Telegraph obituaries of 27 April 2012:
Baroness Ritchie of Brompton, who has died aged 66, was the stepmother of the film director Guy Ritchie and thus former stepmother-in-law to the pop diva Madonna; in Conservative circles, however, she was known as a formidable figure in local government and the force behind the Tory drive for more women MPs.
Shireen Olive Folkard was born on June 22 1945. Her father was an Arabist (the name Shireen is Persian) in the Colonial Office, and her early years were spent in Yemen. At the age of seven she was sent to boarding school in “cold, grey England”, which she hated. When she was 10, her parents returned from Yemen and their marriage broke up. … Later she discovered that her mother, whom she had believed to be adopted, was in fact her grandmother’s natural daughter, but not by her grandfather, and born two years before their marriage. ...
She ... married John Williams, with whom she had a son, but the marriage broke up and soon afterwards she met John Ritchie, who was divorced from his first wife. After their marriage in 1982, Shireen gave up work and became stepmother to his children, Tabitha and Guy. ...
http://www.telegraph.co.uk/news/obituaries/9229647/Baroness-Ritchie-of-Brompton.html
Shireen Olive FOLKARD (1945-2012). She was d of Lionel Harvey FOLKARD (1919-94) and Edwina May SOAMES (1912-2003). She was cr a LP as Baroness Ritchie of Brompton, of Brompton in the Royal Borough of Kensington and Chelsea. She m 1st 1968 (reg December, Chelsea, div ?) Alexander D M GRAY [obit says John WILLIAMS?] and had a son, Oliver. She m 2nd 1982 John Vivian RITCHIE (father of Guy, the film director and former Madonna husband), no issue.
RITCHIE Shireen, Olive (née Folkard) Baroness Ritchie of Brompton. Died peacefully in her sleep on 24th April. Beloved wife of John. Adored mother of Oliver and stepmother to Tabitha and Guy. Politician, mentor and dog lover. Funeral private; Thanksgiving Service, 12 noon, 18th October, Chelsea Old Church. No flowers, donations to Trinity Hospice.