John Turner, known professionally as John Nathan-Turner, was an English television producer. He was the ninth producer of the long-running BBC science fiction series Doctor Who and the final producer of the series' first run on television (from 1980 until it was cancelled in 1989). He finished the role having become the longest-serving Doctor Who producer and cast Peter Davison, Colin Baker and Sylvester McCoy as the Fifth, Sixth and Seventh Doctors, respectively.