BUSINESS users switching from diesel to petrol could see a 35% fuel bill rise, TMC is warning ahead of a predicted anti-diesel Budget tomorrow (22 November).

The fuel and mileage cost management specialist is echoing other fleet industry experts in urging the Chancellor to think very hard before raising diesel taxes.

Paul Hollick, managing director of TMC, which captures mileage, fuel and telematics information on over 100,000 vehicles, said: “Contrary to what the Chancellor may be being told, petrol vehicles are nowhere near closing the mpg gap to diesels in the real world.

“Clumsily trying to push fleets and drivers away from new diesels would hit businesses, crimp consumer spending and reverse the trend toward lower greenhouse gas emissions. It would do more harm than good.”

Sampling data from over 8,000 vehicles, TMC showed that diesels averaged 49.8mpg in real-world use compared with 36mpg for petrol cars and 41.6mpg for petrol hybrids. The cost of fuel for the diesels in the sample averaged 11.2p per mile but petrol averaged 15.2p per mile – 35% higher.

For the average diesel driver, switching to a petrol car would add nearly £400 to their fuel bill over 10,000 miles (£1,122 for diesel vs. £1,515 for petrol).

Reports in usually well-informed news media suggest the Budget will impose a new levy, or even a higher rate of VAT, on diesel sales – new vehicles and/or the fuel.

Mr Hollick questioned what would be achieved by penalising new diesels, which are fitted with technology that greatly reduces the nitrogen oxide (NOx) and particulate emissions that are partially blamed for air quality problems in some UK city centres.

“I would like to see the government produce convincing figures to show that today’s diesels contribute disproportionately to the problem. Or how hurting fleets, the biggest market for clean diesels, would have any effect on the number of older, dirtier diesels on the roads,” he said.

“If the Budget measures get it wrong, it won’t just be a case of shutting the stable door after the horse has bolted. It would be like having the horse come back cleaner, healthier and more useful than before, and turning it away again.”

Mike Thompson, brand manager at leasing broker Leasing Options, added that diesel sales had already been affected with a 14.9% drop in diesel registrations in the year to October.

“While we don’t expect to see an immediate big impact in the car leasing industry, we feel sure that we will see a steady increase in petrol and hybrid car requests within the next six months,” said Mr Thompson.

How diesel v petrol compares

• See on our sister title Business Car Manager how Diesel v Petrol compares for business with Volvo’s new T4 petrol option for S90/V90