A surge in the price of supermarket fuel has pushed the average price of a gallon of diesel close to 5.
The average UK diesel price is now 109.2p, which is 494.43p a gallon. The 5-a-gallon mark will be hit when diesel prices reach 110p a litre.
Fuel prices levelled at the end of 2007, but have risen again in January because several supermarkets have dropped low-cost promotions.
On average, supermarket fuel has risen by 1.78p per litre for petrol and 1.71p a litre for diesel in the past month, compared with rises of 1.36p and 1.19p respectively for non-supermarket fuel.