In 1993 he was made resident dramatist at the Northcott Theatre in Exeter, the youngest playwright to be honoured by the Arts Council in this way, and for them he wrote a series of plays, including his controversial comic fable about God living in suburbia, Breaking Bread Together, which later was revived in London.
His association with his mentor, Alan Ayckbourn, has been particularly fruitful, with White Lies, About Colin, and Knights in Plastic Armour proving especially popular.
This was, at Davies' request, a re-working of the themes introduced in Shearman's earlier Big Finish audio play Jubilee.
In the same year, Mad Norwegian Press published Wanting to Believe, a book by Shearman that examines The X-Files and its spin-off series (Millennium and The Lone Gunmen) in a critical fashion.
Also in 2009, Shearman collaborated with comedian Toby Hadoke to watch and comment on every episode of Doctor Who from the programme's debut in 1963 to David Tennant's final story.
The resulting discussions are being published by Mad Norwegian Press in three volumes as Running Through Corridors: Rob and Toby's Marathon Watch of Doctor Who.
Shearman describes himself as a comedy writer, but it might be truer to call him an absurdist; most of his work, whatever the medium it is written for, is concerned with the effect on ordinary people when they're propelled into extraordinary or fantastical situations.
His controversial early play, Easy Laughter, purports to be a Christmas domestic comedy, but eventually reveals itself to be set in an alternate history where the season celebrates not only the birth of Jesus but the successful extermination of the Jewish race.