1. John Leeson is a British actor who is best known for voicing K-9 on the television series Doctor Who from 1977 to 1979, then from 1980 to 1981, and has returned for two single episode in the revived series.
2. He also embarked on a parallel career in voiceover work, freelancing as a continuity announcer with BFBS Television in Germany, BBC Television, and in the early days of Channel 4.
3. Tom Baker detested the character of K-9, but luckily got on very well with Leeson .
4. Leeson however became frustrated himself with the limitations of the character, and left the programme after the conclusion of the 16th season in 1979.
5. He was also seen on-screen that season as the character Dugeen during the serial The Power of Kroll .
6. Although the character was, eventually, not killed off, merely written out, Leeson agreed to return.
7. Leeson also agreed to return to voice K-9 in K-9 and Company , a spin-off from Doctor Who which was not picked up after the airing of its pilot episode.
8. He also voiced K-9 for the 20th anniversary episode of Doctor Who, The Five Doctors, though it was little more than a cameo appearance.
9. He also voiced K-9 for its return in the 2006 Doctor Who episode “School Reunion”, then its cameo in the pilot episode of The Sarah Jane Adventures.
10. The most recent occasion of Leeson voicing K-9 is in the spin-off television series, K-9.
11. Leeson also voiced K-9 in a Doctor Who-themed episode of The Weakest Link and the video game Lego Dimensions.
12. In November 2013, Leeson appeared in the one-off 50th anniversary comedy homage The Five Doctors Reboot.