As a result petrol and diesel now typically costs more than £3 a gallon. Keith Greenhead, director of fuel at PHH Vehicle Management, said: 'Unless prices at a petrol station are considerably lower than average, driving a few extra miles to another station will probably cost more.'
PHH has calculated that drivers of a 1.8-litre petrol-engined car which typically costs 9p a mile in fuel to run (based on 32mpg and fuel at 62p a litre/282p), will cancel out a 2p a litre saving if they detour more than six miles each way, a 3p saving more than eight miles each way and a 4p saving more than 11 miles each way.
Greenhead said: 'The actual cost of taking a 12-mile detour to save £1 is nearly £7! When depreciation on the vehicle and the cost of the driver's time are added to the expense of the fuel, every mile travelled costs a whopping 56p.' Meanwhile, PHH also claimed that fleets were being charged the same price for ultra-low sulphur diesel as for regular diesel this week despite the duty differentials announced by the Chancellor.