Political opposition to first generation biofuels appears to be strengthening after reports emerged today that UK Prime Minister Gordon Brown has requested that the issue of food shortages and biofuels' contribution to rising food prices should be put on the agenda at the upcoming G8 summit in Japan this July.

According to reports in The Guardian, Brown has written to fellow G8 leaders raising fears that burgeoning demand for biofuel crops such as corn, soy and palm oil is eating into agricultural land that is desperately needed for food production.

The letter comes in the wake of an official UN warning earlier this week that food shortages and soaring prices could lead to riots and political instability around the globe. That warning was followed by a World Bank report yesterday which claimed demand for biofuels had contributed to an 83 per cent increase in food prices over the past three years.

In his letter to the Japanese Prime Minister, Yasuo Fukuda, Brown wrote that there was a need to address the knock on impact increased demand for biofuels is having on food production. "There is a growing consensus that we need urgently to examine the impact on food prices of different kinds and production methods of biofuels, and ensure that their use is responsible and sustainable," he wrote.

Brown is now also expected to raise the issue with US leaders at upcoming meetsing in Washington and New York next week.

The letter will add fresh momentum to calls from environmentalists for the UK to scrap its target to ensure that five per cent of transport fuel comes from biofuels by 2010 until a recently commissioned government review into their sustainability is completed. Critics of first generation biofuels claim that as well as leading to increased food prices they can lead to a net increase in carbon emissions as forested land is often cleared to make way for new energy crop plantations.

The move will also be seen as another blow to the biofuels sector, which has seen plummeting stock prices over the past year and has faced near constant criticism from green groups that it is failing to deliver on promised environmental benefits. However, advocates of the technology it can still have a role to play in curbing carbon emissions as long as so-called second generation biofuels are developed that can be made from waste plant matter and crops such as grass that can be grown on non-agricultural land.