Ed Miliband will stand in for Andy Burnham on an emergency G7 call to discuss world energy markets as the Prime Minister attends his father’s funeral.
It comes as US President Donald Trump wrote on his Truth Social platform that “Europe has just agreed to release a massive amount of their heavily stocked diesel oil”.
This process “will begin immediately”, he added.
Mr Miliband, the Foreign Secretary, is expected to join French President Emmanuel Macron and other leaders for the talks on Friday afternoon amid US pressure on European countries to use their reserves.
Ministers have sought to reassure the public amid concerns about supply as prices reached £2 a litre for the first time.
The previous record high was 199.09p, set in June 2022 after Russia’s invasion of Ukraine.
Mr Trump has said he “may” call for Europe to draw down on its stores as he considers introducing an export ban on American diesel.
Prices have rocketed in recent months because of the disruption in global markets caused by the US-Israeli conflict with Iran and Russia’s ongoing war in Ukraine.
Speaking to broadcasters on Friday morning, transport minister Keir Mather insisted Britain’s supply is “robust” and the country has a wide range of sources.
“I want to reassure people this morning that the United Kingdom has got a diverse range of supply when it comes to diesel,” he said.
“We have resilience built into our system for that reason.
“We are working very closely with our US counterparts to stress the importance of that relationship, and the importance of sustaining flows of diesel around the world, but also working through international fora in the International Energy Agency and partners in Europe from whom we get a proportion of our diesel imports as well.”
He added: “Although prices have gone up at the pump, the Government is aware of that and the freeze in fuel duty is still in place.
“People shouldn’t be concerned about shortages because of the inherent resilience that is built into that system.”
RAC head of policy Simon Williams said the price rises are showing “no signs” of slowing down.
He said: “The cost of filling up an average family car is now £110, almost £32 more than it was at the start of the US and Iran war.
“This will be very challenging for households and companies that drive a lot of miles, from commuters, haulage and delivery firms, businesses with large fleets all the way through to sole traders.
“In a cruel twist, it’s diesel vehicles, which were once considered the most cost-effective option for lengthy journeys, that are now burning a hole in people’s pockets.”
As a member of the International Energy Agency, the UK is required to keep oil stocks equal to at least 90 days of net oil imports in reserve.
If Washington introduces a ban on exporting diesel, Britain would be forced to compete with other countries for an alternative.
The UK imports nearly 55% of the diesel it uses, with the US accounting for around 31% of that.
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