Riley visited the Cheltenham Ladies ' College, Haberdashers ' schools Aske's School for Girls and Berkhamsted School. In 2003 she was for the first time on television with a guest role in Agatha Christie: Poirot. Her stage debut followed In 2005 , with a supporting role in a play performance of The Philadelphia Story. She made her film debut in the same year, with the portrayal of Mary Bennet in Pride and Prejudice (2005). She played her first leading role in St Trinian's (2007 film), a film starring Rupert Everett, Colin Firth, Russell Brand and Gemma Arterton. Then she appeared as a music lover from the 60 's in The Boat That Rocked (2009).
Riley is married to entrepreneur Elon Muskin 2010, in Scotland.
|Filmography as an actress|
|2007||Nearly Famous||Lilac||7 episodes|
|2008||Doctor Who||Miss Evangelista||2 episodes|
|2005||Pride and Prejudice||Mary Bennet|
|2006||Marple: The Moving Finger||Megan Hunter||Television film|
|2007||Friends Forever||Grace||Short film|
|St Trinian's||Annabelle Fritton|
|2008||The Summer House||Jane||Short film|
|Phoo Action||Lady Elenor Rigsby||Television film|
|2009||The Boat That Rocked||Marianne|
|2012||The Liability||The Girl|