One of Costa's earliest television roles was as a pupil in Steven Moffat's sitcom Chalk.
In 1997 he starred as Eric Slatt in two series of Steven Moffat's Chalk, contributing to the audio commentaries for the DVD release in 2008.
In 1997 he appeared as Mr Carkdale, the English teacher who spoke only in Anglo-Saxon, in two series of Steven Moffat's school-sitcom Chalk.
Steven Spielberg | Steven Seagal | Steven Soderbergh | Steven Holl | Steven Tyler | Steven Isserlis | Steven Gerrard | Steven Curtis Chapman | Steven Berkoff | Steven Wilson | Steven Pinker | Steven Levy | Steven Moffat | Steven 'Bo' Keeley | Allan Moffat | Steven Weinberg | Steven Meisel | Steven Hyde | Steven Ford | Steven Stucky | Steven Dann | Steven | Steven Yeun | Steven Webber | Steven T. Seagle | Steven R. Smith | Steven Houghton | Steven Hirsch | Steven Heighton | Steven Dietz |
The occasional interviews on the main show have included the actors Colin Baker, Deborah Watling, Jules Burt and Eugene Washington, music composers Murray Gold and Mark Ayres and writers John Peel, Steven Moffat, Tom MacRae and Paul Cornell.
After appearing in the 1991 episode of Press Gang “Holding On,” he went on to play estate agent Trevor, Becky’s (Fiona Gillies) lover, in two seasons of Steven Moffat’s Joking Apart.
Steven Moffat contacted Chris Chibnall, asking him to return to writing for Doctor Who.