A five per cent slump in the price of oil last month caused costs at the fuel pump to drop by 2.5p a litre.
Diesel prices posted the steepest drop since January 2016 as the average price fell to 119.54p, and petrol had its largest fall since November with an average of 117.54p, data from RAC Fuel Watch today reveals.
Major supermarkets made two 2p-a-litre cuts over the course of the month, cutting £1.40p off a tank, due to the biggest drop in the price of a barrel of oil since last July.
An average 55-litre family petrol car costs £64.65 to fill up while a diesel car costs £65.75 to fill.
RAC fuel spokesman Simon Williams said future changes to prices depend on whether more is done to curb oil supply.
"The Organisation of the Petroleum Exporting Countries (Opec), together with some non-members, have cut production, but their efforts have been undermined by the US ramping up its fracking production.
Williams added: "The strength of the pound against the dollar is also important as fuel, like oil, is traded in dollars, but having suffered a big drop in the value of the pound after the Brexit vote the new norm seems to be a pound that is consistently worth $1.24. The absence of any further significant downward movement should mean fuel prices will be mostly decided by the oil market."
However, the price of oil has risen to recover from four-month lows on expectations Opec's production cuts will cut the global oversupply.