Her first professional role was as the young Beatrix Potter in the 2006 British-American film Miss Potter. Boynton has said that the first day of filming Miss Potter was "the best day of [her] life."[2] In 2007, Boynton was nominated for the Young Artist Award for Best Performance in a Feature Film – Supporting Young Actress, for Miss Potter, but did not win.She went on to play Posy Fossil in 2007, one of three main characters, in the *** film Ballet Shoes.[3] Posy is a young, ambitious ballerina who is taken under the wing of a prestigious dance academy. Boynton did not actually dance in Ballet Shoes; a body double was used for the dancing scenes. Boynton also played the role of Margaret Dashwood in the *** serial Sense and Sensibility.Lucy most recently filmed the role of Lucia di Narni in BORGIA for Canal+. She recently filmed a guest lead on LEWIS. She appeared in MO with Julie Walters and David Haig. She was in SENSE & SENSIBILITY and BALLET SHOES both for the ***.