The price of diesel rose by 5c a litre in the last month and is now at its highest ever level.
The average price is now 99.4c per litre - making it more expensive than petrol.
According to a fuel price survey by the AA, petrol prices are also rising and have surged by 2.8c per litre in the last month.
The AA is advising drivers to shop around as there can be quite a difference in prices depending on where you go.
