Dobson was a senior computer technician at Space Control and Dr Bruno Taltalian's chief assistant of two years. (TV: The Ambassadors of Death) He was a short, thin-faced dark-haired man with a "mournful" face. (PROSE: The Ambassadors of Death)
Working with Dr Taltalian and General George Carrington, Dobson pretended to help the Third Doctor and Liz Shaw decode the aliens' message using a machine sabotaged by Dr Taltalian. When they began to crack the code, he called Sir James Quinlan and warned him. (TV: The Ambassadors of Death)
Behind the scenes
The character was originally named Dawson until a member of the production team realised there had been a character named Dawson in the previous story. (INFO: The Ambassadors of Death)