"Mary Tamm - Interview". Wireless Theatre Limited. April 2011. Retrieved 14 May 2024. The website displays the recording date as 2016, but Tamm's reference to Elizabeth Sladen's death dates the interview to 20-24 April 2011. At minute 11:40, Tamm recalls she made her decision after only 12 episodes (so at the completion of The Stones of Blood, "So after I dunno, three or four stories, you know, 12 episodes, I realised it wasn't really get going anywhere, the character."