The price of unleaded petrol could surpass that of diesel in the coming days as a result of Hurricane Harvey in the US, the RAC has warned.
The drivers’ association said the price of a litre of unleaded could rise by up to 4p, passing 121p.
That level has not been seen since December 2014.
It follows the shut-down of large oil refineries on the Gulf Coast of America, driving up US demand for petrol imports.
RAC spokesman Pete Williams said: “The average price of a litre of unleaded [in the UK] on Thursday 31 August was 117.29p and diesel was 118.14p.
“But we could see unleaded rise in the coming days to around 121p a litre, with diesel likely to stay stable around 118.5p.
“This will be the first time unleaded has been higher than diesel since June 2016 and we expect this to be the case for some time to come – or at least until the US oil industry is able to get refineries back into operation.”
Hurricane Harvey has killed more than 30 people and destroyed thousands of homes.
One quarter of the oil refining capacity in the US remains offline leaving a shortfall of more than four billion barrels a day.
Crude oil production in the Gulf of Mexico is also down 13.5%.
In response, oil traders are redirecting fuel to the US ahead of the busy Labor Day weekend, which usually sees a surge in travel.