Just a year ago, by his own confession, Sir Richard Branson was a sceptic on global warming. But last week, after a dramatic conversion, he set himself in the forefront of a growing number of businessmen campaigning to stop it running out of control.
The entrepreneur prom- ised to invest $3bn (£1.6bn) over the next 10 years to try to kick-start a green energy revolution to replace, with new clean sources - including biofuels from plants - the fossil fuels that are causing climate change.
His private vision, it is said, is to try to do for renewable energy what private capital did for mobile phones two decades ago - to turn a fringe technology into a universal phenomenon that changes everyone's lives. But is this just one more publicity stunt from a global grandmaster intent on promoting the Virgin brand?
Fresh from his announcement - which dominated last week's meeting of the Clinton Global Initiative in New York - he spoke exclusively to this paper about his motives. For the first time he told the story of his change of heart; it involved both the media giant Ted Turner and Al Gore, the former vice-president of the US.
Global warming, he is now convinced, is nearing "a tipping point", at which it runs irreversibly out of control. Indeed, he says: "We just have to hope that it has not come already. We have to try to do something about it. One way is to try to come up with a clean alternative fuel or fuels."
A great-nephew of Sir Peter Scott, the naturalist who helped found the World Wildlife Fund, Sir Richard has long had an interest in the environment, at one stage running an ill-fated anti-litter campaign for Mrs Thatcher.
But, influenced by Bjorn Lomborg's controversial nay-saying book The Skeptical Environmentalist, he was dubious about global warming. He now confesses that the book "set me back a couple of years".
His reassessment began almost exactly a year ago after Hurricane Katrina, when "fuel prices went through the roof". He tried to find out the reason for the increase and decided that it was a shortage of oil- refining capacity. "I started to build an oil refinery, but then Ted Turner rang me up and asked: 'Why not build a refinery for clean, rather than dirty fuel?'. He invited me to fly to Washington to meet experts."
He went to the United Nations Foundation, a think-tank founded by Mr Turner as part of a $1bn donation to the UN, which has helped lead the way in pushing for biofuels in the US. He had lunch with a small, but distinguished, group including Mr Turner; Senator Tim Wirth, the foundation's president; John Podesta, President Clinton's former chief-of-staff; Boyden Grey, now US ambassador to the EU; and Reid Detchon, head of the Energy Futures Coalition, another Turner initiative.
Mr Detchon recalls that Sir Richard did not seem well informed about biofuels, but "took copious notes and then did what few other people on Earth can do - went back to his office and put serious corporate investment into it. He's an idealistic, dynamic guy, not bound by established corporate bureaucracies."
Sir Richard himself says: "I decided that what they said was right." He joined the steering board of the Energy Future Coalition and made his first green investment - in seven bio-fuel refineries in the west of the US.
He plans to build more refineries in the east of the US, and then invest in biofuels in Britain. And he is in talks with Gordon Brown's officials about changing tax rules to enable him to run Virgin trains partly on them.
Last week's announcement came at the request of Al Gore. The former vice-president spent two hours at Sir Richard's home in July while in Britain for show- ings of his film, An Incon- venient Truth. Sir Richard said: "He came to me and said: 'Do something big to kick-start the process'."
The entrepreneur announced that the money would be invested from the profits of his transport companies, but admits that he suspects he will also have to "strip it from other companies" and borrow on the market. He hopes that other businessmen will invest large sums. It is, he stresses, a business investment, not charity. "The only way that global warming will be beaten is if we can create an alternative fuel industry that pays its way."
But biofuels are controversial, not least in the US, where making them is eating up more of the corn crop, diminishing already depleted food supplies. As this paper reported three weeks ago, the amount used for biofuel will next year exceed US corn exports, which have traditionally helped to feed more than 100 mostly poor countries.
But Sir Richard sees making biofuel from corn as just a first step. He says the holy grail is to develop cellulosic fuel made from crop wastes like stalks, weeds like prairie grass, or simply from rubbish. He estimates that this "dramatic step forward" is four or five years away.
Going further than perhaps he should, he discloses that he is researching yet another possible development, "cellulosic butanol", which he says is a more powerful and convenient environmental fuel than existing biofuels. He says that, unlike them, it could be transported down pipelines and "poured straight into cars", without having to adapt them. He hopes that it might even one day be able to power airliners.
He has another unpublicised project developing wind turbines, together with the motor-racing industry. And this week he will unveil plans for persuading airlines to save energy. He says that if they do not act voluntarily, governments should force them to.
But is this all for real? Isn't it all just about image, about promoting the Virgin brand? "People do things for different reasons, not just one. I have about 10 different reasons for doing this. One is to tackle climate change. Another is to develop a clean fuel industry.
"But I would also love to have Virgin recognised as the most respected brand in the world. If it can be a leader in tackling global warming, and that enhances the brand, that's fine. It will enable us to tackle the problem all the sooner."
More and more top business leaders are taking up environmental issues - both for their own sake, and as good business - and are pressing governments to act.
Chief executive, Marks & Spencer: Under him M&S has brought in Fairtrade clothing, banned 60 pesticides from food, cut energy use and supports sustainable fishing.
Group chief executive, HSBC: Has made HSBC the world's first carbon-neutral bank, funds green initiatives, urges customers to adopt green business practices.
Chief executive, BSkyB: BSkyB can "bring the climate change debate into the household", he says. BSkyB says it is the first carbon-neutral media company.
Chief executive, B&Q: B&Q leads the way with wood from sustainable forests, reduced pollutants in paints, has promoted alternatives to peat and recycles vigorously.Reuse content