Marks & Spencer will work with suppliers to create six “ethical factories” to bolster its commitment to improved labour standards in developing countries.

The initiative, part of a first-year review of M&S’s Plan A social and environmental programme, is one of several measures introduced after the retailer’s “fair partner” credentials were challenged by NGOs last autumn.

No decision has been made about the locations for the factories, but Bangladesh, India and China are likely candidates.

The retailer said the factories would be “in key sourcing countries in order to develop and implement best practices on key issues such as wages, employee representation, productivity and our own purchasing practices”.

Other commitments include making it a condition of trade with M&S that manufacturing sites implement worker rights training and work with the Chartered Institute of Purchasing and Supply to identify “leading responsible buying practices”.

Last year, Retail Week launched its Source for Good campaign to highlight how retailers are improving conditions in supplier countries.

This week, M&S joined grocery giant Tesco in banning cotton sourced from Uzbekistan, over concerns about forced child labour in the country. Tesco clothing chief Terry Green said the practice was unacceptable.