This topic might have a better name.
Broadfell Prison guard (The End of Time)
Talk about it here.
A guard at Broadfell Prison was one of the many that worked under the Governor and Miss Trefusis. She worked alongside Lucy Saxon in an attempt to kill the Saxon Master. Whilst Lucy was imprisoned, she held the potion which could kill the Master and when the revival ceremony took place, she passed it to Lucy and she threw it at the Master. However, she was killed when the prison exploded. (TV: The End of Time)