Catherine Fall

According to the Telegraph:

Met Mr Cameron at Oxford and worked with Mr Osborne in the research department. An identical twin, she is beautiful and enigmatic, preferring to keep out of the limelight. The daughter of a former ambassador, she concentrates on making sure Mr Cameron is always well briefed and on time and ensures he keeps in touch with MPs, donors and dignitaries. She developed her skills working in Michael Howard's office and as director of the think tank The Atlantic Partnership. She is one of the few aides who has a family. Her husband Ralph Ward-Jackson runs the Art London fair and she lives with their two young children, Olivia and Guy, in Battersea.^[1]