LONDON, June 26 -- For 56 years, The World Tonight signed off BBC Radio 4's evening schedule with the institutional calm of something that had always existed and always would. On Thursday, the BBC ended it. The cancellation is among the first specific casualties of what the corporation's new director-general frames as an unavoidable transformation, and what broadcasting unions are calling the most damaging round of self-inflicted cuts in the corporation's recent history.

Matt Brittin, who arrived at BBC headquarters from Google just six weeks ago, announced the elimination of roughly 550 jobs across content, nations and regional journalism, and news divisions on Thursday. The announcement opens a restructuring that targets between 1,800 ...