The rise runs against the UK government's efforts to cut reduce the social and environmental effects of transporting food. In a policy document on food industry sustainability, published this year, government made a commitment to reduce by 20 per cent the distance it takes to transport food from domestic and international suppliers, to supermarkets, through to consumers. The baseline year is 1990.

The strategy is being developed by the Department for the Environment, Food and Rural affairs (Defra). The policy means increased costs for processors and retailers as they attempt to cut CO2 emissions from food transport.

Emissions of CO2 from food transport, including emissions from overseas transport, totalled almost 18 thousand kilotonnes in 2004, a rise of 5.6 per cent, according to a Defra study released last week.

Total CO2 emissions from food transport increased by four per cent between 2002 and 2004, having increased by 15 per cent between 1992 and 2002, the Defra study showed.

Food transport in urban areas, measured in vehicle kilometres from cars, heavy goods vehicles and vans, changed little between 2002 and 2004, having increased by 19 per cent between 1992 and 2002, Defra stated.

Food transport in urban areas by car, measured in vehicle kilometres, decreased by six per cent between 2002 and 2004, having increased by 30 per cent in the previous decade.

Meanwhile food transport in urban areas by heavy goods vehicles, increased by four per cent between 2003 and 2004, after having reduced by eight per cent in the previous six years.

Food transport in urban areas by van increased by 12 per cent between 2003 and 2004.

A government report last year estimated that the direct environmental, social and economic costs of food transport are about £9bn each year. The costs are dominated by the congestion, which accounts for £5bn of the total figure and 50 per cent of the social costs associated with food transport. About £2bn of the costs were attributed to road accidents, £1bn to pollution and £1bn to related costs.

AEA Technology, a consultancy hired to examine measuring the costs suggested that government polices could include:

• sourcing food more locally where appropriate through consumer awareness campaigns, public procurement, support for local food initiatives and the strengthening of UK suppliers;
• reducing car food shopping through home delivery, support for local and in-town shops and the provision of safe cycle and pedestrian access;
• reducing transport impacts through requiring cleaner vehicles, improved logistics and more rail freight;
• internalising the social costs of transport to reflect the costs to society of pollution, congestion, accidents, noise and so on in the prices paid by transport users; and,
• improving the wider sustainability of the food chain through promoting ethical trading and energy efficiency in the local food sector.

"There may be a trade-off effect between food prices and food miles," they stated. "Some policies to reduce food miles could potentially lead to higher food prices. One example would be the internalisation of the social costs of food transport. However, any food price impacts will depend on the combination of policies used and on responses to those policies by consumers, producers and industry."

Over the last fifty years, food miles have risen, driven by a number of factors, including globalisation and a wider sourcing of food within the UK and overseas. Other key drivers include the concentration of the food supply base into fewer, larger suppliers, partly to meet the demand for bulk year-round supply of uniform produce, a switch to routing most goods through supermarket regional distribution centres and a trend towards the use of larger heavy goods vehicles (HGVs).

Food transport accounted for an estimated 30 billion vehicle kilometres in 2002, of which 82 per cent were in the UK. Road transport accounts for most of the vehicle kilometres, split between cars, HGVs and light goods vehicles. Food transport accounts for a quarter of all HGV vehicle kilometres in the UK.

Transport and distribution costs make up about 3.5 per cent of food prices for major retailers. Improvements in the efficiency of their centralised distribution systems should have reduced transport costs, but so far there has been no noticeable effect on food prices, because of the influence of other factors, they stated.

The authors also note that UK supermarket chains are driven by competition and that it may be difficult to squeeze much more out of them. The efficiency is not directly reflected in lower prices for food in UK supermarkets, where prices are 12 per cent to 16 per cent higher than in Europe. Other factors, such as the price of land and the price of fuel in the UK, may be more important factors in the higher costs.