 In addition, Great Northern runs suburban commuter trains in and around north London.In the late 20th century, the area around the station became known for its seedy and downmarket character, and was used as a backdrop for several films as a result.A major redevelopment was undertaken in the 21st century, including restoration of the original roof, and the station became well known for its association with the "Harry Potter" books and films, particularly the fictional Platform 9¾.