Petrol prices hit a new high on Wednesday as motorists faced paying an average of £6 per gallon at garage forecourts for the first time.

The average cost of filling a tank now costs nearly £3.50 more than it did at the start of the year, with petrol prices hitting a new record of 132.12p per litre for unleaded and 137.92p per litre for diesel. The price of Brent crude has risen above $110 per barrel in the wake of political unrest in north Africa and the Middle East, adding to the upward pressure on petrol costs from fuel duty and VAT increases. Edmund King, the president of the AA, urged the government to reduce petrol taxes and VAT.

"In the meantime, drivers are going to have to manage as best as they can, by cutting out journeys, driving more economically and hoping that a stronger pound will cushion some of the blow," King said. "But these high prices are already leaving casualties among drivers, consumers and business."

The trade body for petrol retailers and forecourt operators in the UK has warned that petrol prices could rise by up to another 10p per litre over the next month, due to the rising oil price and a fuel duty increase scheduled for 1 April. The chancellor, George Osborne, has pledged to look at options for mitigating next month's fuel duty increase.

Adrian Tink, motoring strategist at the RAC, said: "Something has to be done to control the price of fuel before driving becomes solely the preserve of the rich." However, one mooted solution to the petrol spike – a fuel-duty stabiliser – has been dismissed by some doubters as unworkable. Osborne's coalition colleague, Vince Cable, has warned that implementing a stabiliser, which raises and lowers petrol taxes according to oil prices, would pose "real technical difficulties".