The cost of filling up a family car will rise by £8 if predicted oil price rises materialise, a motoring firm has warned.

Petrol and diesel prices have already risen to a three-and-a-half-year high, driven by the rapidly rising cost of oil.

The barrel price of oil reached 80 US dollars this week and the boss of energy giant Total believes it could return to 100 US dollars in the coming months.

If this happens then the RAC believes fuel prices could soar to £1.41 per litre for unleaded and £1.44 for diesel.

This would mean filling up a 55-litre car would cost £78 for petrol models and £79 for diesels – up £8 on existing prices.

Average UK forecourt prices currently stand at £1.24 for unleaded and £1.28 for diesel.

RAC fuel spokesman Simon Williams said: “Fuel prices are now at their highest since mid-October 2014 and sadly the worst may be still yet to come.

“If the price of oil goes up towards 100 US dollars a barrel we will very likely see a return to the dark days of April 2012 when petrol and diesel hit record highs.

“Even though the oil price was higher then (around 120 US dollars a barrel) today’s weaker exchange rate will lead to similar prices at the pumps.

“This will inevitably force families to make some tough choices about how they spend their money.”