Christopher Eccleston auditioned for the role of Stuart Jones. He withdrew himself from consideration shortly after his audition, saying he felt he was "too old" for the part. When he withdrew, he recommended they audition Aidan Gillen.
The character of Vince is a Doctor Who fan - both creator/writer/producer Russell T. Davies and script editor Matt Jones are fans of Doctor Who (1963) and wrote spin-off novels for Virgin Publishing in the mid-1990s. Davies later became executive producer of Doctor Who (2005) and hired Jones to write for series two.
A follow-up, spin-off series ("Misfits") was initially commissioned by Channel 4 due to the show's success. It would have followed the characters of Hazel, Alexander and Bernard from the original series, while introducing new characters. Although Russell T. Davies developed draft scripts for four episodes and storylines for a further 22, the series was cancelled before it went into production.
Episodes 5 and 6 were originally to have been written by another writer. However when early drafts proved unsatisfactory, the writer was fired and 'Russell T Davies' elected to write the entire series himself. As a result of this, episodes 5 and 6 were written after episode 7 (but before episode 8) and were somewhat lacking in plot. Davies has never revealed which writer let them down.
The role of Alexander was written for Phil Collinson, a good friend of writer and creator Russell T. Davies. However when Antony Cotton arrived for the audition, everyone agreed that he was better suited to the role. Collinson went on to be a producer, and was hired by Davies to produce Doctor Who (2005).