Britain's organic food revolution is spreading across all sectors and social classes, according to new figures which show that the market has surged well past £1bn a year.

The Soil Association's annual audit for 2004 reveals that overall sales were up by 11 per cent to £1.2bn.

The rise comes amid concern about the level of pesticides sprayed on conventional food.

Supermarkets, which have been accused of rejecting imperfect produce, squeezing farmers and importing too much, have seen their share of the organic market shrink.

The Soil Association's figures - released today - show that sales of organic food direct from the producer - by boxes, farm shop or farmers' market - rose by a third.

The public is also buying far more organic food from independent shops, where sales have rocketed by 43 per cent.

Supermarkets still sell most organic food - £913m a year - but their share of the overall market fell from 81 per cent to 75 per cent.

Meanwhile, far more people from lower social and economic groups are going organic. According to the research, 58 per cent, 48 per cent and 55 per cent respectively of classes C2, D and E now say they eat organic.

Parents also seem more likely to buy organic food for their children. Sales of organic baby foods rose by 6 per cent - compared with 1 per cent for non-organic - between 2003 and 2004.

More organic than non-organic baby meals are now being bought and the market is worth £51m a year.

In recent years, the market for organic drinks has also grown, particularly of wine and beer.

Organic fruit and vegetables grown on the UK's 4,000 organic and converting-to-organic farms may only be treated with a few naturally-occurring chemicals.

"This report shows that the popularity of organic food is growing steadily," says Patrick Holden, the director of the Soil Association, which certifies 75 per cent of organic produce in Britain.

"Increasing numbers of people are eager to buy local, to obtain the freshest organic food possible and to cut down on environmental pollution."