By Susannah Cullinane BBC News

Pollution from cars is thought to contribute to global warming

Environmental groups have condemned the chancellor's call for an increase in oil production, saying it clashes with the government's climate change policy.

Protests against the fuel tax are being planned after the price of unleaded reached �1 a litre in parts of the UK.

Gordon Brown has said price rises are an economic risk and is calling for 500,000 extra barrels of oil a day.

Greenpeace accused him of "hypocrisy" and "short-termism" and Friends of the Earth said it was a knee-jerk response.

If people buy more fuel efficient vehicles they'll save much more than even if Gordon Brown was going to take 10p off the price Mike Childs Friends of the Earth

At a meeting of EU finance ministers in Manchester over the weekend, Mr Brown said the high price of fuel posed a significant risk to the European economy and to global growth.

He urged the Organisation of Petroleum Exporting Countries (Opec) to raise production by half a million barrels a day.

He also said another 1.5 million barrels a day released by Opec after Hurricane Katrina should be extended for a longer period.

Crude oil prices reached more than 70 dollars a barrel following the disruption caused to the US industry by the hurricane.

Greenhouse gases

Mr Brown added that EU ministers were "committed to developing more effective international co-operation on energy efficiency and clean technologies".

But Mike Childs, campaigns manager for Friends of the Earth, said: "It's Gordon Brown's responsibility to see the bigger picture rather than reacting with a knee-jerk response... and the bigger picture is climate change."

Many scientists believe gases produced by burning fossil fuels are contributing to an increase in the earth's temperature known as the "greenhouse effect".

The greenhouse effect is thought to be responsible for rising sea-levels and extreme weather patterns.

Britain is a signatory of the Kyoto Protocol on climate change which aims to curb member states' greenhouse gas emissions.

'Fuel addiction'

Mr Childs said the government needed to encourage Britons to buy "greener" cars rather than increase demand for fuel.

"He should be saying he wants to invest heavily in weaning the country off carbon fuels, as opposed by trying to play to the tabloids by calling for more oil to be produced.

"... If people buy more fuel-efficient vehicles they'll save much more than even if Gordon Brown was going to take 10p off the price."

Mr Childs said the Labour government had promised to make climate change a priority and to put that to one side "was a tragic mistake".

Ministers should be investing much more into renewable energy rather than trying to protect oil. Mark Strutt Greenpeac

Mark Strutt, a climate campaigner at Greenpeace, said high fuel prices were "exactly what we need to help us get off our addiction to oil".

"Rising oil prices are starting to curb demand for oil and that's actually what the British government wants: to reduce demand for fossil fuels.

"To now increase production of oil to try and bring prices back down is irresponsible - particularly in terms of extreme weather events, which are increasing in frequency.

"Britain should be thinking more about climate change and less about the short-termist production of oil."

Renewable energy

Mr Strutt said oil would continue to get more expensive because of its role in climate change as well as the security situation in some oil-producing nations.

"Ministers should be investing much more into renewable energy rather than trying to protect oil."

He said plans for building renewable energy sources were being hindered by a lack of investment from government.

One of the main barriers for power companies setting up wind farms, for example, was the cost of the transmission lines to the national grid, Mr Strutt said.

"The government is saying 'you've got to pay for connections to that'.

"The government should be paying for that - it's something they could do with the money from the increased revenue from the high price of oil."