According to the Independent newspaper, it's because "this is not a degree for the old fashioned but for future managers. A new dawn of librarian has arrived...are you in? ... These days the degree is really broad and is a cross between computer science and management." The Independent A-Z of Degrees August 2009 As you will see, their objective overview of Library and IM degrees around the country places the University of Sheffield firmly at the front.
The Information School at the University of Sheffield - Number One in the World for Library & Information Management (QS World University Rankings by Subject 2023)