Seebohm Rowntree was the son of the wealthy Quaker businessman Joseph Rowntree, but acutely aware of the poverty that surrounded him in late-Victorian York. In 1899 he set himself the task of defining a “poverty line” by working out how much it would cost to supply basic food, housing and clothes. Anyone who couldn’t afford to buy those basics – including a helping of pease pudding with bacon on Sunday – was below the poverty line.

The idea of a poverty line has stayed with us, but the candidates have multiplied. The World Bank has two poverty lines: a dollar a day and two dollars a day (strictly, those are 1985 dollars adjusted for inflation). In the US, the poverty line is $29.58 a day for a single adult under the age of 65. All these are absolute income standards, just as Rowntree’s was.