Diesel should be cheaper than petrol. It would be good national housekeeping. There is more mileage in a barrel of Brent Crude cracked into diesel than there is in a barrel refined into petrol. The AA is quite right in its September fuel report to question the premium of 4.4p a litre, revealing that three times this year the wholesale price of petrol has been the same as diesel. For nearly four weeks in the spring, DERV cost the same at the refinery, sometimes it was 2p a litre cheaper. The variation is smaller this month, but diesel still costs more on the forecourts and tax makes things worse. Diesel drivers, the AA tells us, spend £2.5 million a day extra, which pretty well cancels out the advantages of buying an economical diesel car.

That is not how it should be. The Office of Fair Trading is looking into oil and fuel prices, but won’t report until next year. Talk of publishing a wholesale price indicator stopped with a reshuffle of transport ministers.

Edmund King, the sometimes over-chatty president of the AA rightly says, “Putting Justine Greening’s initiative on hold has given fuel retailers and suppliers the cover to perpetuate the petrol-diesel price gap for the next four months. The AA welcomes the OFT investigation but not at the expense of immediate and easily-achieved price transparency.” During a backbench debate, two Conservative MPs supported the initiative, while a shadow energy minister pressed the Government to get on with it.

“If the EU can publish a weekly track of petrol and diesel wholesale prices in euros per tonne, why can’t the UK publish an equivalent in pounds per tonne or pence per litre? It doesn’t need an investigation, or permission of the fuel retailers or suppliers, just a form that can be understood, to ensure a fair price.”

DERV: Army nomenclature. Diesel Engined Road Vehicle, fuel for the use of.
BMW 120d convertible, tested Isle of Bute, August 2008.