Siân Phillips
From Tardis Wiki, the free Doctor Who reference
Dame Siân Phillips (born 14 May 1933[1]) voiced several characters for Big Finish Productions.
She was once married to Robin Sachs.
She was considered to play Adrasta in The Creature from the Pit. (INFO: The Creature from the Pit)
She is best known for playing Livia in I, Claudius.