Lucy Rownham is Bernard's younger cousin and is portrayed by Elizabeth Mellor. She makes her first appearance in the Original series in the series 3 episode Visiting Time in which she stays round Bernard's house while her mother is in hospital for an operation. Lucy is very demanding but she starts to become more favourable towards Bernard after he helps her to visit her mother using the watch. She becomes a main character in series 4 in which she stays at Bernard's house for the rest of the school year and attends Bernard's school as her parents had to go to America for work. She joins them along with Bernard and his parents at the end of the third series in Time's Up. She finds out about the watch in Time Loop after she finds it lying around and gets stuck in a time loop and in frozen time until the Postman helps her after which Bernard starts letting her borrow it occasionally.
Like Bernard she also uses the watch to solve everyday problems and help people though this almost led to Bernard stopping her from borrowing the watch in Helping Time when her attempts to help backfire and she tapes the head teacher's wrists to his chair.