The Sunday Times has found that home-grown products are being transported thousands of miles overseas for processing before being put on sale back in Britain.

Scottish prawns are being hand-shelled in China, Atlantic haddock caught off Scotland is being prepared in Poland and Welsh cockles are being sent to Holland to be put in jars before going on sale in Britain.

Meanwhile, products grown overseas are taking circuitous routes to Britain. African-grown coffee is being packed 3,500 miles away in India, Canadian prawns are processed in Iceland, and Bolivian nuts are being packed in Italy.

While ethical consumers have long opted for organic and fair trade products, there is now an increasing focus on cutting “food miles”, which generate unnecessary carbon emissions, contributing to global warming.

David Miliband, the environment secretary, has said he believes environmental labelling will in future be routinely available on products, along with nutritional information.

Supermarkets are working to environmental transport group, said: “We are producing food in one corner of the world, packing it in another and then shipping it somewhere else. It’s mad.”

Dawnfresh, a Scottish seafood company that supplies supermarkets and other large retailers, cut 70 jobs last year after deciding to ship its scampi more than 5,000 miles to China to be shelled by hand, then shipped back to the River Clyde in Scotland and breaded for sale in Britain.

The company said it was forced to make the move by commercial pressures. “This seems a bizarre thing to do but the reality is that the numbers don’t stack up any other way,” said Andrew Stapley, a director. “We are not the first in the industry to have had to do this. Sadly, it’s cheaper to process overseas than in the UK and companies like us are having to do this to remain competitive.”

Haddock is one of the fish most commonly caught by British trawlers, but Tesco sends its Atlantic haddock for processing to Poland where labour costs are lower. It is then driven more than 850 miles to Tesco’s depot in Daventry, Northamptonshire.

Organic and fair trade producers are also guilty of notching up excess food miles by sending their goods from country to country. Traidcraft coffee, sold at Sainsbury’s, is made from beans grown in Bukoba, Tanzania.

Once the coffee is cultivated, it is driven 656 miles to Dar-es-Salaam and then shipped 3,250 miles to Vijayawada in India where it is packed. The coffee is loaded back on the ships and transported another 5,000 miles to Southampton. It is then driven 330 miles to Gateshead and is finally driven to Leeds for distribution to Sainsbury’s stores.

Traidcraft says it aims to reduce its environmental impact, but maintains that by packing its coffee in India it is helping employ 500 people. It said information was provided to customers on the source and the location of the packaging operations.

Sainsbury’s organic fair trade rice, produced in the lush foothills of the Himalayas, is shipped to Lille, France, rather than Britain, to be packed. It then makes a second journey to end up on Sainsbury’s shelves.

It is not just fair trade coffee that is sent from country to country. Instead of directly importing coffee beans from Costa Rica for their instant coffee, Sainsbury’s and Tesco first send them to Germany. The final product then undergoes another 500-mile lorry journey to get to Britain.

Similarly, French-grown walnuts sold in Waitrose are sent to Naples to be packed. The retailer’s Brazil nuts from South America are also transported to Italy before being sent to Britain.

Inadequate labelling means it is impossible for a consumer to calculate the food miles of many products. Much of Britain’s canned tuna is processed in Thailand and the Seychelles, but the catches come from several countries, including France, which are not usually disclosed.

Caroline Lucas, the Green party MEP, said: “Ultimately, the price is paid by all of us in the shape of higher greenhouse gas emissions, air pollution and congestion, and food that is both less tasty and less healthy.”

The industrialisation of the food chain means even small firms are being forced to ship their produce abroad for processing. Pilchard fillets, produced by the Pilchard Works in Cornwall, are sent on the overnight ferry to France because there is no suitable processing plant in England. The pilchards are canned in Douarnenez in Brittany, then returned to Cornwall.

Similarly, Welsh cockles – produced by Van Smirren Seafoods – are driven across Britain to Dover and then transported to Yerseke in Holland. They are pickled and put in jars before being sent back to Britain.

A 2005 study by the Department for Environment, Food and Rural Affairs estimated that domestic and international food transport for the UK market produces more than 19m tons of carbon dioxide and costs more than £9 billion a year in environmental, economic and social terms.

Young’s Seafood, criticised last year for sending langoustines to Thailand for processing, has commissioned a study on the environmental impact of its decision. It insists there was a “marginal” impact on carbon emissions because the Far East operations are done by hand, rather than by machine.

Supermarkets are reluctant to label products with food miles, but Tesco has said it will introduce labels on 70,000 products showing the total “carbon footprint” caused by transport and production. Additional reporting: Mary Rachel Meyer

Information printed on food labels about ‘country of origin’ can often be confusing or misleading thanks to a maze of different rules

- Meat products do not have to be labelled with the country of origin. This means companies such as Bernard Matthews can import meat from eastern Europe and label it as British produce after it is reshaped and breaded

- The main ingredients of processed food do not have to be labelled with their country of origin. This means the ‘food miles’ in most products, such as jams, juices and ready meals, are concealed from consumers

- Some food products can be described as coming from several countries as there is no requirement to give a single country of origin if firm buys product from different sources. Chicken breast may be labelled as from ‘EU, Brazil or Thailand’

For general information on how to read a food label, visit

www.eatwell.gov.uk/foodlabels/

www.food.gov.uk/foodlabelling/

www.foodcomm.org.uk/latest_scrambled_eggs_jan05.htm

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• Alex Rider exclusive: Incident in Nice
• Green & confused: do energy-saving bulbs work?
• Let’s skip lunch, say the hungry generation