David Cameron and Barack Obama are discussing plans to force down the price of petrol by releasing reserves of oil to boost global supply.
Petrol prices in Britain have risen by 3.5p (4.2c) a litre over the past month to a record high, and the cost of filling the tank of a family car is threatening to become a major political issue in Britain and America.
Yesterday, during a trip to New York on the final day of his official US visit, Britain's prime minister said he wanted to "help families" struggling with petrol prices.
He told students at New York University: "The price in Britain is considerably higher than here.
"I won't tell you what it is -- it would probably make you faint."
Earlier, Mr Cameron said: "We didn't reach a decision about oil reserves but we discussed the issue and I think it is important that we do what we can to try to help families who are trying to make their family budgets add up."
British chancellor George Osborne is under pressure to delay planned rises in fuel duty in next week's budget, although he has indicated he will push ahead with the increase.
It is understood that under the plan being discussed, the Americans would release for sale some of the 700 million barrels of oil they hold in reserve.
As the British Government does not hold significant reserves, it is expected to reduce the level of minimum reserves it currently demands that oil companies hold. (© Daily Telegraph, London)