the service was first broadcast by the british broadcasting corporation in 1928 and, except for 1930, has been broadcast every year since, even throughout world war ii in spite of the stained glass having been removed from the chapel and the lack of heating. the service is slightly different today: not all the readings are from the bible. most of the carols are sung by the choir. there are generally more than nine carols. the service starts with the famous carol "once in royal david's city". verse one is always sung as an unaccompanied solo by one of the boys in the choir. the boy is not told that he is the one who has been chosen to sing the solo until just before the service begins.