The pound fell to its lowest level since decimalisation against the US dollar on Monday.

The fall of the pound is likely to cause the cost of petrol and diesel to soar at a time when high costs at the pump have become the norm. According to the AA, poorly performing Sterling is already adding almost £5 more to the cost of filling up a vehicle.

A litre of petrol cost an average of 163.75p on Monday, while diesel was 180.31p per litre, according to the Department for Business, Energy and Industrial Strategy.

The RAC has agreed with the warning issued by the AA, with Simon Williams, the RAC’s fuel spokesman, saying: “A falling pound is bad news for drivers at the pumps because wholesale fuel, like oil, is traded in dollars.

“Fortunately, wholesale petrol and diesel costs have reduced in recent weeks due to the price of oil coming down which has led to lower prices at the pumps.

“But if oil were to go back up, the weak pound would definitely lead to drivers paying far more to fill up.”