The Road Haulage Association (RHA) has asked the Office of Fair Trading (OFT) to launch an inquiry into why diesel remains so much more expensive than petrol. RHA chief executive Roger King says: "We were told earlier this year that the reason diesel prices were then some 14p/litre or 15p/litre more than the equivalent petrol price was due to world demand and a shortage of refining capacity.
"Perhaps this was understandable when oil prices reached $143/barrel, but now that we are talking $50/barrel, it must be because demand has reduced as a result of a slowdown in global activity.
"Our question to the OFT and to the oil producers is why this hasn't been reflected in the diesel premium we are still paying? The UK haulage fleet alone is not doing the mileage it was earlier this year and many of our members have confirmed that they have mothballed trucks as 
the recession reduces economic activity.
"So why haven't diesel prices come down to their traditional parity level with petrol?"