Downing Street has welcomed President George Bush's call for a 20% cut in US petrol usage by 2017. Prime Minister Tony Blair's official spokesman said the proposal - which he characterised as a firm commitment on the President's part - was a step towards a new framework to tackle global warming after the Kyoto Protocol runs out in 2012.

It is hoped that an outline of this framework can be in place by the time of the G8 summit of industrialised countries in Germany in June, he said.
In his State of the Union address in Washington last night, Bush urged Congress to expand the use of alternative fuels - mainly ethanol - in an effort to slow America's ever-growing consumption of oil.

Bush said his proposals would help the US cut oil imports by the equivalent of 75% of what it receives from the Middle East, reducing its reliance on overseas suppliers for its energy. But he put greatest stress on scientific advances, rather than reductions in consumption, to cut America's fuel use.

"America is on the verge of technological breakthroughs that will enable us to live our lives less dependent on oil," he said. "These technologies will help us become better stewards of the environment, and they will help us to confront the serious challenge of global climate change."

Blair's official spokesman said: "What the President did announce was a commitment to reducing gasoline usage in the United States by 20% by 2017. I think that counts in my book as a firm commitment. This obviously fits into a situation where we have a momentum building up, not just in the States - if you look at California for example - but also worldwide on energy and climate change."