Clue: Witch runs traveller over in coming back to Biblical city (8)
Answer: GOMORRAH
Explanation: Witch runs traveller over in coming back to Biblical city (8)
<=HA(R + ROM + O)G 
where HAG is "witch", R is "runs", ROM is "traveller" and O is "over".
 
Rom is a word for a Gypsy boy or man, so "traveller"