John Black directed the penultimate Fourth Doctor serial The Keeper of Traken (1981), which saw the first appearance of companion Nyssa, and the second Fifth Doctor serial Four to Doomsday (1982).
He was also responsible for directing the only K9 and Company story, A Girl's Best Friend. However, according to Ian Sears, he was not respected on the set and he was given the nickname "John Grey".[1]