COST-conscious companies which insist their drivers shop around for lower priced fuel, may not save themselves any money if their drivers go too far out of their way, according to PHH Vehicle Management. Budget fuel duty rises has meant most pump prices increasing nationwide.

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.