Stephen's experience in theatre began at the newly-opened National Theatre in the mid 1970s where he worked as a translator of modern and classical German plays, until his own original work began to be produced.
In Brighton in the mid 1980s Stephen co-founded the shortlived Thumbscrew Theatre, and in 1987 Alarmist Theatre which continued to produce and tour plays in until the late 1990s. These companies produced many of Stephen's early plays, adaptations and translations.
Between 1987 and 2004, parallel with the running of Alarmist Theatre and the editing of The Printer's Devil magazine, Stephen was Writer-in Residence at Lewes Prison. While working at the prison, he invited in a music theatre workshop team from Glyndebourne. This workshop became an annual event, and led to Stephen's longstanding involvement with the opera house. He was the librettist for the Glyndebourne children's opera Misper(1997) and their youth opera Zoë (2000). Subsequently he was commissioned with composer John Lunn to write Zoë for Glyndebourne on Tour (2005).
In 2004 he provided the libretto for Sir Harrison Birtwistle's chamber opera The Io Passion. He also wrote the text for Birtwistle's carol The Gleam, which was performed by the Choir of Kings College Cambridge in the Service of Nine Lessons and Carols and broadcast on Radio 4 on Christmas Eve 2003, and for Birtwistle's oratorio for the Bach Festival in Leipzig 2010 - Angel Fighter.
Before working in the opera, much of Stephen's theatre work was produced and directed by Alison Edgar, artistic director of Shaker Productions who were based at the Hawth in Crawley, including the nationally acclaimed Trunks, and the trilogy of short comedies, The Last Post, The Shortlist and The Milk Train, which appeared in successive seasons of Briefs, Edgar's annual selection of short plays. The Last Post was made into a short film by Sarah Radclyffe Productions and nominated for a BAFTA in 1996.
In 2009 the BBC broadcast his radio series The Romantic Road, part travelogue, part biography, in which he revisted the home cities of the German idealist philosophers who influenced his life.
Stephen is married to the opera singer Marcia Bellamy. They live in Brighton with their three children.