The shift to Fairtrade tea at Café Revive follows the success of its switch to Fairtrade coffee last year. The retailer insists customers will not be charged extra for the product.
The Fairtrade Foundation estimates that 'out-of-home' Fairtrade coffee sales in the UK will increase by 23 per cent and Fairtrade tea by 11 per cent over the next 12 months as a direct result of the move.
M&S also sells Fairtrade-certified fresh produce, such as avocados, bananas, mangos and pineapples.
'Our customers have told us they not only want products that taste great, but also ensure the farmers get a fair price for their crops,' said M&S chief executive Stuart Rose.