Between 1886 and 1902, Charles Booth survey first East London and then London as a whole, eventually publishing 17 volumes of what he called 'impressions of degrees of poverty'. Booth collected information from school board visitors (school attendance officers) and cross-checked this with information he gathered from local people including clergy and also from his own investigators who lived for a time in poor communities - Beatrice Webb (nee Potter) was one of them. He also gathered household budgets from 30 families. From this mass of data, Booth classified London residents, claiming that 30% were living 'in poverty or in want', by poverty he meant 'having no surplus'. Booth's work drew attention to the reality that the poor were not feckless and unable to help themselves. He carried out this research while living at the Toynbee Hall settlement.
Source: C. Booth (1903) Life and Labour of the People of London, London: Macmillan; Pat Thane (1996) Foundations of the Welfare State, Harlow, Essex: Longman.