Transportation ballads are a genre of broadside ballad some of which became an important part of the folk song traditions of Britain and Ireland. They concern the transportation of convicted criminals firstly to the American colonies and then to penal colonies in Australia. Transportation ballads were published as broadsides, (song sheets sold cheaply in the streets, at markets and at fairs). Many have passed into the folk tradition and have been collected subsequently from traditional singers. Ewan McColl wrote: