Another Government U-turn could be on the cards amid mounting anger over the rising cost of motoring.Senior Labour sources are indicating new road and fuel taxes could be watered down or even scrapped.Any changes will be revealed in Chancellor Alistair Darling's pre-Budget report in the Autumn.Mr Darling and Prime Minister Gordon Brown are meeting energy leaders in Scotland later to discuss soaring prices.Lorry drivers are threatening to step up their protest unless ministers take action.Cabinet colleagues insist the Prime Minister is "listening" to anger over the planned increase in vehicle excise duty on higher-polluting vehicles expected to hit nearly 18 million people.But Mr Brown has warned there is "no easy answer" to the global oil problem as the world faces its "third great oil shock".The Prime Minister called on nations to unite to stabilise the price of oil which has increased from $10 a barrel a decade ago to $135 today.Mr Brown's comments come a day after he was besieged by hundreds of lorry drivers demanding he help save the haulage industry by reducing the duty on diesel.He said: "I know that families up and down the country are feeling the impact in the cost of filling up at the petrol station and in the rise in gas and electricity bills."The cause of rising prices is clear: growing demand and too little supply to meet it both now and - perhaps of even greater significance - in the future."Our goal that Britain becomes a low-carbon economy is now an economic priority as well as an environmental imperative."