Sally Llewellyn's love of drama started with school Shakespeare, followed by a degree in English Literature at Sussex University. She developed her playwriting skills at Player-Playwrights; Chelsea Theatre's writing course, Rome Wasn't Built in a Day; and with Hackney stage writers group Alive and Kicking. Her full-length play Edward's Presents was produced in 2004 at the Union Theatre in Southwark.
While writing The Barrier, Sally also ventured into performance: she developed the character Angie in Arcola Theatre's Faces in the Window (Arcola, 2010), and wrote and played the character Bet, a Victorian prostitute, in the Dickens-inspired The Uncommercial Traveller (Arcola and Punchdrunk, 2011).
Sally writes drama about difficult emotive subjects, as a way to understand them more deeply. ''She explains that The Barrier tries to reflect the complex reality of Stamford Hill and the tensions that spring from having such different communities living together. Llewellyn hopes that by unpacking these tensions as impartially as possible the play will enable audiences to gain more understanding of and empathy for the Hasidic community, and for their non-Hasidic neighbours, and for other people in similar circumstances". (Interview with Carolin Kopplin, UK Theatre Network 23/9/2013)