John Harrison was the PR of Serf Systems, but was actually in charge of the business, using a hologram of Joseph Serf to run the company.
Harrison accessed the black market of alien species, paying millions to gain a group of Skullions, who crash-landed in central Asia, as slaves. Harrison forced them to maintain a hologram of Joseph Serf, the real Serf having died in a skiing accident in Val d'Isère in 2007.
He controlled them using neck collars which would electrify when he activated his pen. Harrison's pen had 10 levels of punishment; level 10 would kill. Harrison wanted to make profit by selling the SerfBoard to everyone using Serf's hypnotic ability. The fake Serf said that the SerfBoard was revolutionary while in reality it was, in Harrison's own words, "rubbish". Harrison's pen was destroyed by Lionel Carson who had been hypnotised by Serf. His plot was foiled by Sarah Jane Smith. Luke Smith made the hologram convince people to not care about the SerfBoard. Sarah Jane had a ship sent from Skultos to rescue the Skullions. However, an angry Harrison advanced on the Skullions as they were transported to the ship, resulting in him being transported as well. The ship then left Earth, and Luke hoped that the Skullions would make Harrison work for them this time. (TV: The Man Who Never Was)
Personality
Harrison was a cold-hearted businessman, who didn't care about anyone else. He believed that the exchange of money for services and goods, even goods such as slaves, were the way of the world. He was only interested in making profit from the SerfBoards. He didn't care about the Skullions' pain and when Plark told him that they were thirsty, Harrison sadistically sprayed water, which burned Skullions, on them, indicating that they were not to stop working. (TV: The Man Who Never Was)