The other co-writer is Arthur Mathews (Graham Linehan’s co-writer on Father Ted). A blurb:

Steven Toast is a successful actor. Now in his forties, Toast regularly appears in prestigious television dramas, and on the London stage.

However, he has made a recent career faux pas by electing to star in a new controversial west end stage play. The play is considered so outrageous, that Toast is frequently attacked by appalled members of the British public.

Recently divorced, Toast is staying with his friend Ed Howzer. Black and Ed’s elderly mistress, the agoraphobic Goodhouse.

In the pilot episode Toast is asked to audition for the long running television series, Inspector Somerset. However, the producer has been recently imprisoned for racial chanting on the set of his own production, so Toast has to audition for the part of a gay corrupt detective during prisoner’s visiting time.

More info from Channel 4’s press release (it also outlines other shows they’ll be airing).