under the UK retailer's Plan A “eco-plan”.

The firm, which first launched its Plan A environmental initiative in 2007, wants all M&S products to become ‘Plan A products’ with “at least” one sustainable or ethical quality.

This will involve converting 50% of its 2.7bn individual M&S clothing, food and home items into ‘Plan A products’ by 2015 and 100% by 2020.

The retailer hopes the fresh impetus behind the plan will see its 2,000 suppliers adopt Plan A "best practice" and encourage M&S customers and employees to live ‘greener’ lifestyles.

Under the fresh plans, M&S wants to “bring clarity to the living-wage debate" by determining and agreeing a fair, living wage for its workers in Bangladesh, Sri Lanka and India. Other plans include M&S helping suppliers create more “ethical or environmental” features in its factories.

M&S chairman Sir Stuart Rose said: “Since we launched our eco plan, Plan A, in 2007 we’ve reduced our environmental impact, developed new sustainable products and services, helped improve the lives of people in our local communities and saved around GBP50m by being more efficient.

“We’ve now set ourselves the ambitious target of becoming the world’s most sustainable retailer by 2015, so that we lead the way in making a positive contribution to the environment and society across everything we do and everything we sell.”

In addition, the retailer is to launch a ‘Your Green Idea’ competition for it customers in a bid to encourage them to “live a more sustainable lifestyle”. The winner will receive GBP100,000 to be spent on ‘greening’ an organization such as a school, charity or small business.