Boris Johnson and US president Joe Biden are at odds over a plane to cut the production of green fuels in a bid to free up land for food production.
The prime minister wants G7 leaders to temporarily cut the amount of grain produced for biofuels, claiming the process is pushing up the cost of food.
Britain is backed by Germany – also pushing for a temporary waiver on their biofuel commitments – but the US and Canada are against the move.
American officials have said Mr Biden will block the plan in a bid to protect the lucrative US market for ethanol and biodiesels and the country’s climate change commitments.
German officials are downbeat on the chances of an agreement. Chancellor Olaf Scholz is said to expect the other G7 countries will reject a temporary waiver on the green fuels.
Asked about the US torpedoing the plan, environment secretary George Eustice told Sky News: “We should still argue for the right thing. They disagree with it because they are thinking as well about their fuel supply … We think that is misplaced.”
Mr Johnson’s plan to scale back biofuel use would mean reneging on the government’s own net zero strategy in which it pledged to increase its production.
The International Energy Agency (IEA) has said replacing fossil fuels with biofuels is one of the primary ways to decarbonise the transport sector.
However, a growing number of environmentalists question the use of biofuels. Although it is a renewable form of energy, the water-intensive process uses a lot of agricultural land and has seen more deforestation.
The think tank Green Alliance has said ending biofuel production in the UK would free up food for 3.5 million people and reduce food prices.
Britain’s biofuel industry has grown from almost nothing in 2005 to an industry supplying 293 million litres in 2020 – largely to the transport industry, according to the government
But the huge amounts of land used to grow crops which go on to be burnt in combustion engines, is now under scrutiny with calls for farmers to return focus to food production instead.
Ahead of talks on food security on Monday, Mr Johnson said: “From emergency food aid to reviewing our own biofuel use, the UK is playing its part to address this pernicious global crisis.”
He said that Putin’s “craven blockade” of millions of tonnes of grain meant “the world’s poorest people are inching closer to starvation”.
Russia’s blockade of the Black Sea has driven up global food prices, and aid charities have warned that it has placed 47 million people around the world on the brink of a humanitarian disaster.
Around 25 million tonnes of corn and wheat cannot be exported and is currently at risk of rotting in Ukrainian silos.
Almuth Ernsting, co-director of campaign group BiofuelWatch said: “Ending the use of food to make biofuels would immediately relieve food prices and protect millions from going without enough food.”
Mr Johnson’s government will pledge £10m to help rebuild Ukraine’s railways in a bid to use trains to export grain trapped by Vladimir Putin’s blockade in the Black Sea.
The PM said the UN plan to start negotiations involving Turkey to get grain out of Ukraine is a “non-starter” because Russia will continue to use food supply as a bargaining chip to ease sanctions.
President Volodymyr Zelensky will urge the G7 to provide more military support on Monday, addressing leaders by video link from Kyiv as his country continues to come under attack from Putin’s missiles.
