In his childhood, Clive was interested in a variety of mysteries, including Big Foot, Sasquatch, the Mary Celeste, yeti, the Bermuda Triangle, the Loch Ness Monster, the Roswell crash, and the panthers of Dartmoor.
On 24 December 1979, when Clive was fourteen, he encountered the Twelfth Doctor at a newsagents and noticed that the Doctor was using coins from 1987. He followed the Doctor back to the TARDIS and jumped in after him. As it was Christmas Eve, the Doctor decided to give Clive the gift of a quick trip in time and space.
Clive decided that he wanted the Doctor to take him to Loch Ness in the summer of 1979 to try to find the monster. After an adventure involving a plot by the Meddling Monk to depopulate the Earth and then sell it, the Doctor returned Clive to Christmas Eve. The Doctor used his mental powers to blur Clive's memories of the incident. (PROSE: The Persistence of Memory)
Rose Tyler contacted Clive shortly after having her own encounters with the Ninth Doctor. Clive said "the Doctor" was held to be a title handed down from father to son, while he believed that the Doctor was an immortal alien. He showed Rose photographs and drawings of the incarnation she had met, taken at several different points in history.
Clive had a wife, Caroline, and a son. Shortly after his meeting with Rose, his family and he were on a shopping trip at Queen's Arcade when the Autons were activated. Clive was amazed to realise that the stories he had heard about the Doctor were true. However, an Auton approached his family and drew its gun on Clive. Clive stared at it with a look of cold submissiveness, knowing he was about to be killed. He was then shot dead by the Auton, while his family fled for their lives screaming. (TV: Rose)