Millions of motorists are facing a rough ride after petrol prices rose for a second straight month.
Unleaded jumped 2p a litre in March to 122.58p, after rising almost a penny in February, the RAC said.
Drivers are now paying £67.22 to fill up compared to £66.31 four weeks ago.
Diesel increased by 0.7p per litre to an average of £71.87 for a full tank.
Simon Williams, from the RAC, said further price hikes were likely.
He blamed “the worst possible combination” of a weak pound and reduced supply from oil producers.
But a supermarket price war could ease the pain.
Williams said: “They have 45% of the market which means everyone has to compete with them.”
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Three consecutive months of fuel price reductions came to an end in February as retailers "instantly" passed on wholesale price rises, the RAC found.
Motorists had enjoyed a decrease in fuel costs during the previous three months, when petrol dropped by 11p per litre and diesel fell by 8p per litre.
But in February the average price of a litre of unleaded rose by nearly a penny to £1.20, while diesel was up by just over a penny to £1.29, according to RAC Fuel Watch.
