Supermarkets are failing UK farmers by importing substantial amounts of organic produce, according to the Soil Association.

In a new report the association says that the big chains are buying fresh vegetables and meat from abroad, even when the produce is in season in the UK.

The survey found that just 19 per cent of Asda’s organic onions came from the UK. Most other chains fared little better, with 20 per cent at the Co-op, 23 per cent at Sainsbury’s and 26 per cent at Safeway sourced from UK growers.

A representative of the Soil Association said: “Considering that onions grow well in the UK, this is a very disappointing result.”

The survey conducted between November 15 and December 15 was based on nearly 1,000 results from supporters who visited stores to check produce labels.

The British Retail Consortium said the report was selective and unrepresentative. A spokesman said: “By carrying out its survey before the UK growing season is under way and only asking its own members the Soil Association is not giving a true picture of the amount of UK organic produce sold through UK retail outlets.”