the band strikes up with a squeeeeeeeze and a squaaaawwwwk and charges boldly into the hand-clapping , foot-stomping , whistle-blowing ballad of jemmy twitcher jemmy twitcher - a cunning highwayman who appears as a member of macheath 's gang in the beggar 's opera ( 1728 ) by john gay ( 1685-1732 ) .