Regarding the Orson Welles broadcast, here is something interesting from the Wikipedia entry on Msgr. Ronald Knox:
In January 1926, for one of his regular BBC Radio programmes, Knox broadcast a simulated live report of revolution sweeping across London entitled Broadcasting from the Barricades. In addition to live reports of several people, including a government minister, being lynched, his broadcast mixed supposed band music from the Savoy Hotel with the hotel's purported destruction by trench mortars. The Houses of Parliament and the clock tower were also said to have been flattened. Four months later there was considerable public disorder during the General Strike so the possibility of a revolution was real at the time. Because the broadcast occurred on a snowy weekend, much of the United Kingdom was unable to get the newspapers until days later. The lack of newspapers caused a minor panic, as it was believed that this was caused by the events in London.A 2005 BBC report on the broadcast suggests that the innovative style of Knox's programme may have influenced Orson Welles's radio broadcast "The War of the Worlds" (1938), which it foreshadowed in its consequences. In an interview for the book This is Orson Welles, Welles himself said that the broadcast gave him the idea for "The War of the Worlds".