Stephen is the uncle to Dave and Molly, and is left in charge of them when their parents go on a round-the-world tour. It is never mentioned how he was chosen to be their guardian, or what his exact relationship with the children is. He is often the main subject of Basil or another character's jokes, much to his annoyance. He lives with the majority of the main characters in his flat.
He was also not very clever as he did not seem to know a very simple sum (as established in the episode, Bing Trouble when Molly told him that 2 + 2 = 4, to which he said "Does it?"). He was played by Christopher Pizzey and left at the end of series 4. He appeared briefly in Series 5 when Basil mentioned that he has been snapped up by Hollywood. But this later reveals he is working at a Hollywood burger van. His cousin Liam arrived to take his place.