Arriving at the summit, British Prime Minister David Cameron, whose government is advancing plans to exploit his country's shale gas deposits, said Europe could not afford to be left behind as the world scrambles to develop the resource.

He drew a comparison with the United States, where years of extraction, using a much-criticised process of hydraulic 'fracking', has delivered record-low gas prices for consumers.

"We mustn't be left behind in the global race," Cameron told reporters. "Europe has 75 percent of the United States's shale resources, but America is drilling 100 times faster than Europe."

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