Surely few will argue that poverty comes cheap. Poverty is a master issue found to amplify nearly all other forms of social difficulty from tooth decay to car accidents and much worse things like cancer and house fires. Public sector finances are merely the first, strongest indicator of the cost of poverty. In the case of Great Britain this effect is captured only too well in the new report at the link below. Serious stuff. Seventy-eight billion pounds worth.
Counting the cost of UK poverty
Joseph Rowntree Foundation (92-page .pdf file)