Punshon was one of the six pilots of the prototype TARDIS. (AUDIO: Collision Course)
The Eighth Doctor encountered Punshon's Matrix spirit. (AUDIO: Lies in Ruins) Punshon was split in two during the crash in the altered time line with one half being in the 1960s and the other in the 1970s. The Seventh Doctor and Ace with the help of Intrusion Counter-Measures Group got the two halves together to stop the time distortion. Punshon died in the process. (AUDIO: The Split Infinitive)