[baroness meta] it would be very, very few people anywhere who knew about oleg. you don't want anybody at any stage to betray the source, because accidents happen. usually, things are very, very carefully contained. only people who need to know. that's a great principle, "need to know." you have to keep completely tight to a very few people. [announcer] a specially extended nine o'clock news with michael buerk. [buerk] president brezhnev, ruler of russia for nearly two decades, is dead. for the soviet people tonight, five days of mourning begin. for the leaders who've grown old in his shadow, the chance of ultimate power.