Fairtrade sales increased by 12% last year to more than £1.3 billion, prompting claims the movement chimes with the current desire for "responsible capitalism".

The increase in sales is lower than 2010's 40% rise, but the sector continues to perform strongly despite tough economic times which saw the UK's gross domestic product, a broad measure of the wider economy, grow at just 0.8% in 2011.

Sales of cocoa products such as chocolate bars carrying the Fairtrade mark, which pays producers a fair price and a premium for community projects, grew by a third (34%) in 2011, while sugar sales increased by more than a fifth (21%).

The commitment by Morrisons to switch all the sugars it sells in its supermarkets to Fairtrade, by stocking Tate & Lyle, brings Fairtrade's share of the UK bagged sugar market to 42%. Tate & Lyle became the first major brand to switch to Fairtrade in 2008, while Sainsbury's and the Co-operative own brand sugars are all Fairtrade and other supermarkets sell some sugar carrying the mark.

The Fairtrade Foundation is calling on the industry to help tip the balance and achieve a 50% market share for bagged sugar.

Many brands also now use Fairtrade sugar, including Cadbury Dairy Milk and Kit Kat four-finger, while Maltesers is switching this year. Ben & Jerry's is also converting all its ice cream to Fairtrade this year.

Elsewhere, the Co-operative is marking Fairtrade Fortnight by switching all its bananas to Fairtrade, with the fruit supplied by a 50-50 split between producer co-operatives and smallholders.

Sainsbury's is putting QR codes on its Fairtrade products, which customers can scan with a smartphone linking them to the company's website where they can learn about the producers growing bananas, coffee, tea, cotton T-shirts and roses.

Marks & Spencer will be selling the first ever tea grown and packed at Iri-iani, a smallholder group of producers in Kenya which it has shared expertise and skills under a scheme part-funded by the Department for International Development.

The Fairtrade Foundation's executive director Harriet Lamb said: "Fairtrade is an example of responsible capitalism in action. "We believe that responsible businesses are those who don't just tackle the company bonuses at the top - but also take steps to ensure a fairer deal for the workers and farmers at the bottom of the supply chain too."