Cerise Davies

 was a scavenger in the London Underground. She lived on the Northern Line. She used to be a doctor, before the government brought in robot doctors. She gave Flip Jackson some water before she told Flip and the Sixth Doctor the way out. Because she was a doctor, she noticed the symptoms of withdrawal in her patients and started collecting rainwater. After Pan Connell's actions she was promoted to a knight. She looked after Flip when she was infected with Velena. (AUDIO: Antidote to Oblivion)