From [[Main_Page|Pilkipedia]], the Karl Pilkington encyclopaedia

Karl has an older brother named Mark. Mark is about 10 years older than Karl, and could be described as a bit of a tearaway. When Karl was first asked about his relationship with his brother commented that he had not seen his brother in 10 years. Also, Karl regularly refers to him as "our kid".

Karl's memories of his brother are not endearing. One particularly unpleasant incident was when, after having several alcoholic beverages, he destroyed Karl's new train set on Christmas Day. This is one of the events that lead to Karl's dislike of Christmas. Other times Mark would bring women into the house while their parents were away. He would barter with Karl to keep silent about it (like letting him ride the tractor through the house). Karl has also alluded to Mark's having been in prison multiple times, as when once Ricky made a joke about a possible nickname for Mark, Karl replied that "he's never out of prison long enough to get a nickname".

Mark is infamous in Pilkington Lore for his exploits in the army. Initially, he got out of fighting in the war in the Falklands because his mother called his commanding officer and begged for him to be kept out of harm's way. Mark's problems in the army worsened when he was discovered to be having an affair with his commanding officer's missus. Eventually he was kicked out for driving a tank down the high street to get a packet of fags.

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