In addition to her chairmanship of the British Transport Police Authority, Millie is chair of Working Links and the Nominet Trust.

She has held several non-executive appointments including a non-executive director of the Cabinet Office, Channel 4 TV, the Prisons Board, the Peabody Trust, Barts Health and Ofcom.

She was also the Chair of Postwatch, and the postal regulator Postcomm and the Carnegie UK Trust.

Millie studied at Camden School for Girls and University College London. She also studied at Greenwich University from where she has an honorary doctorate. She was the High Sheriff of Greater London for the year 2012-13.