However, in the 1920s, the collapse of the sugarcane industry, concomitant with the failure of the cocoa industry, resulted in widespread depression among the rural and agricultural workers in Trinidad, and encouraged the rise of a labour movement. Conditions on the islands worsened in the 1930s with the onset of the Great Depression, with an outbreak of labour riots occurring in 1937 which resulted in several deaths. The labour movement aimed to unite the urban working class and agricultural labour class; the key figures being Arthur Cipriani, who led the Trinidad Workingmen's Association (TWA), and Tubal Uriah "Buzz" Butler of the British Empire Citizens' and Workers' Home Rule Party. As the movement developed calls for greater autonomy from British colonial rule became widespread; this effort was severely undermined by the British Home Office and by the British-educated Trinidadian elite, many of whom were descended from the plantocracy class.