During the First World War there is evidence that some workhouses were used as makeshift hospitals for wounded servicemen. Numbers using the Poor Law system increased during the interwar years and between 1921 and 1938 despite the extension of unemployment insurance to virtually all workers except the self-employed. Many of these workers were provided with outdoor relief. One aspect of the Poor Law that continued to cause resentment was that the burden of poor relief was not shared equally by rich and poor areas but, rather, fell most heavily on those areas in which poverty was at its worst. This was a central issue in the Poplar Rates Rebellion led by George Lansbury and others in 1921. Lansbury had in 1911 written a provocative attack on the workhouse system in a pamphlet entitled ""Smash Up the Workhouse!"".