Asda and Tesco have been accused of breaching international labour standards at clothing factories in Bangladesh.

Workers at the factories work up to 80 hours a week for as little as 4p an hour, according to an investigation by the Guardian. Clothing retailer Primark also came under fire in the report.

Asda said it would reaudit all its factories in the country while Tesco said that although the allegations were serious, it could not investigate them without further detail.