the series stars georgina sherrington and felicity jones (as mildred hubble and ethel hallow respectively), and was broadcast from 1998 to 2001 on itv, and later on hbo. the series also stars veteran british actress una stubbs as the eccentric chanting teacher, miss bat. felicity jones was replaced by katy allen after the first series. it was explained away as a magical makeover (a "witch-over"). new characters were also added, such as frank blossom (the school's caretaker), miss crotchet, the music teacher in the third series who replaced miss bat and two students from ethnic minorities – black ruby cherrytree and jadu wali. new recurring characters included merlin langstaff, a wizard apprentice who befriended mildred, his two mean-spirited acquaintances – barry "baz" dragonsbane and gary "gaz" grailquest, charlie, frank blossom's nephew who really wanted to be a wizard, mrs. cosie, the nervous owner of the nearby tearoom and mistress hecketty broomhead, the evil school inspector who later became a brief headmistress. also as a character who appears more than once is egbert hellibore, chief wizard and headmaster of camelot castle, where merlin, charlie, baz and gaz live. the first series dramatised "the worst witch" and "the worst witch strikes again", and the second series dramatised "a bad spell for the worst witch" and "the worst witch all at sea". both of these two series also contained original stories. the third and final series continued with purely original material.