This is Gallifrey: Our Childhood, Our Home

 was. . . ''a piece written by Murray Gold. It was used in the series 3 episode Last of the Time Lords. A partial version of the theme played near the end of the episode, starting with Master's death and ending with The Doctor walking away from his pyre.

Episodes used in
''Series 3 (Doctor Who)
 * Utopia (TV story)
 * The Sound of Drums
 * The Last of the Time Lords
 * The Doctor's Daughter
 * The End of Time (TV story)''