The company, which already has a 10 per cent share of the world market in technology to convert sunlight into electricity, will aim to achieve $1 billion (about £600 million) in annual sales from this segment of its business over the next decade.

But John Browne, BP group chief executive who announced the target in a speech at Stanford University in California, stressed that the contibution from solar power was likely to supplement, rather than replace, oil and gas as a principal source of energy.

The plans to expand solar energy activities were welcomed by Greenpeace environmental campaigners who last month scaled BP's exploration headquarters in Aberdeen to fit solar panels in protest against the start of production from the company's first Altantic oilfield.

But Chris Rose, a Greenpeace spokesperson, claimed the oil company still failed to recognise the inescapable logic that avoidance of dangerous climatic change would require phasing out of oil and gas use.

"Greenpeace will therefore continue to oppose BP and other oil companies which continue to expand the oil reserves of industrial coustries," he added.

While disagreeing with environmentalists who called for the abandonment of oil and gas exploration, Mr Browne said he believed solar power was among alternative energy sources which offered to make a significant contribution to future needs.

He said even the best methods available at present made solar power twice as expensive as electricity produced by conventional means. But he added: "Technology is advancing and with appropriate public support and investment, I'm convinced we can make solar competitive in supplying peak electricity demand within 10 years."

He announced that BP - which at present has solar power operations in 16 countries - planned significant investment in the US with a new solar energy manufacturing unit due to open in California before the end of the year as part of the company's contribution towards meeting concerns about carbon dioxide emissions and climatic change.

"These are the initial steps. We're examining what else we should do."