"The Worst Witch", a TV series based on the books, starring Georgina Sherrington and Felicity Jones as Mildred Hubble and Ethel Hallow respectively, was broadcast from 1998 to 2001. It was shot in Montreal, London and Cardiff. The series is mostly shot in studio in London, with some episodes filmed in Montreal, Quebec, Canada. The exteriors of Cackle's Academy used Castell Coch, a castle located near Cardiff. The courtyard was filmed at Loseley Park, near Guildford. Inside the school (Great Hall, classrooms etc.) was filmed at Twickenham Studios.