Sly was appointed Chief Executive in February 2003. She started her media career in advertising sales at the Guardian and then The Independent. In 1989 she joined IPC Media Limited as Head of Classified Advertising Sales and joined their Board in 1994 as Advertising Director. In 1997 Sly was appointed Managing Director of IPC tx, the TV listings division. In December 1999 she was appointed Chief Executive of IPC Media Limited and subsequently led the sale of the business to AOL Time Warner. p>
In November 2009, Sly was appointed non-executive director of Ladbrokes plc. She is also on the Board of The English National Ballet School and is a non-executive director of the Press Association and President of NewstrAid, a charity for the wholesale and retail news trade. Sly was previously Senior Independent Director and Remuneration Committee Chairman of EMI plc and a non-executive director of Littlewoods Plc.