Claire (The Office of Never Was)
Talk about it here.
"Claire" was the name a girl gave herself after losing her memory and forgetting her name. Ianto Jones found her in an office block near Splott. She was apparently the security guard. She didn't know the way out when asked. She theorised that the company which had owned the office had died. She found a pile of dead bodies in cupboard. She gave up working with Oliver and left in the lift to her death. (AUDIO: The Office of Never Was)