A cockney gentlemen who shows up unexpectedly when ghosts are bothering the living. Doesn't actully help the people being tormented by spirits, but acknowledges that, yes, ghosts are problematic.
First appears in Episode 21: One Missed Call.
"Oliver Sudden. OWL-EE-VAH Sudden. Oh, oi could tell tales, that oi could. Bob's yer uncle, nod's as good as a wink."