Danny Alexander: Petrol prices "must fall faster" PETROL FIRMS and supermarkets will be pressed by the Government to pass on the benefit of falling oil prices to customers filling up at the pumps. Treasury Chief Secretary Danny Alexander will demand an assurance from fuel companies and distributors that they are doing all they can to pass on the price cuts to motorists. Mr Alexander will use a speech in Aberdeen to warn people would "rightly be angry" if they felt prices were not coming down as much as they should. Brent crude slumped as low as 82 dollars a barrel earlier this week, its lowest level in just over four years due to concerns about over-supply. Mr Alexander will say that consumers feel pump prices rise "like a rocket" when oil costs go up, but fall "like a feather" when they come down. The Liberal Democrat Cabinet minister will say: "Especially in the current economic circumstances people would rightly be angry if they feel that pump prices don't fall as much as they should on the back of falling oil prices. I believe it's called the rocket and feather effect. The public have a suspicion that when the price of oil rises, pump prices go up like a rocket. But when the price of oil falls, pump prices drift down like a feather. This has been investigated before and no conclusive evidence was found. But even if there were a suspicion it could be true this time it would be an outrage. Mr Alexander said he would write to the industry's major players "seeking their assurance that they are doing all they can to pass on the benefit of falling oil prices as quickly as possible." "When the price of oil falls, the public have a right to expect pump prices to fall like a stone, not a feather," he will say. Highlighting the Treasury's action to freeze fuel duty, Mr Alexander will say: "I have made sure over the last four years that Government has helped with the cost of fuel. And when the oil price falls, industry must do all it can to help too. The No vote in Scotland could result in a 2p-a-litre dip in fuel prices at the pumps, according to the AA