The true price of a pair of jeans should be €33 higher than current price shop owners pay, to make sure workers get proper incomes and to protect the environment, according to a new report by the Impact Institute for ABN Amro.

The €33 ‘true price gap’ reflects the difference in the price that a shop pays for a pair of jeans and what it really costs to make them. The ‘real cost’ includes items such as the environmental impact and proper wages and secondary working conditions.

‘Jeans are the symbol of individual expression and freedom, but a lot goes wrong in the production chain,’ the bank said. In total, the jeans market generated retail sales of €42bn in 2017.

The researchers followed the complete chain, from the cotton fields and denim production plants in India to the manufacturing centres in Bangladesh and shipment on to Europe.

In particular, cheap labour, and forced child labour, enable companies to keep wage costs down in the cotton fields, the researchers say. Denim production also requires a lot of water, and is highly polluting.

If these hidden costs were all made clear, consumers could make a better informed choice about the jeans they buy, said ABN Amro retail sector spokesman Henk Hofstede.

The report also includes a number of recommendations to improve conditions in the jeans sector.