https://www.nationalarchives.gov.uk/education/resources/thirties-britain/dimbleby-coronation/
https://www.nationalarchives.gov.uk/documents/audio/dimbleby-on-the-coronation.mp3 Letter from the BBC to the Metropolitan police, 3rd April 1937 (MEPO 2/3896)...
on thenational archivesdimblebycoronation