Highgate (The End of the Beginning)
From Tardis Wiki, the free Doctor Who reference
Highgate was a reformed vampire. The Doctor showed him the straight and narrow but checked in on him every 30 years. In 1999, the Eighth Doctor came to check on him and Highgate told him of the rogue vampire Dwayne Pherber. He helped to defeat Pherber and then committed suicide, realising that he had lived as long as he wanted. He gave the Doctor a gift he was once given by Gostak. (AUDIO: The End of the Beginning)