Leading international supermarket chains, including Tesco, have joined forces to develop a draft code of workplace standards in their global operations.

Tesco, US retailer Wal-Mart, French group Carrefour, Germany's Metro and Swiss chain Migros have created a code called the Global Social Compliance Programme, which includes standards drawn from the companies' existing codes of ethics, and aims to tackle problems such as child labour and unpaid wages, according to the Financial Times.

A draft code was approved by CIES, the food business forum, last month and more details are expected next month, the paper added.