Zac Goldsmith defines himself as "a punter", and reckons he has just taken his greatest ever gamble. For the young multi-millionaire - who combines a love of poker with being Britain's most prominent voice of radical environmentalism - has just agreed to help form the Conservative Party's election platform.
Three days into his leadership last week, David Cameron appointed the 30-year-old editor of The Ecologist as deputy head of a new group charged with overhauling his party's green policies - and putting them at the top of the Conservative agenda. It is potentially the most important moment yet in the evolution of environmental policies in Britain, and Goldsmith, who used to treat political leaders with coruscating scorn and once said he might become an "eco-terrorist" - is "excited".
"I am very, very cynical, and have never had much affection for politicians", he told The Independent on Sunday yesterday. "But I am a punter, and a punter does not punt unless he has a chance of winning.
"I am not politically ambitious, and I do not need a career in this world", adds the inheritor of much of his father, the entrepreneur Sir James Goldsmith's, fortunes. "But I am genuinely excited by the opportunity that David Cameron has opened up.
"It's a punt. But I am not going to put myself in a position where I betray the things I believe in."
The new Tory leader has also taken a gamble with the appointment, a public relations coup of early-Blairite brilliance, symbolising his determination to revolutionise his party's image. Cameron has seen an opportunity both to seize a popular issue long neglected by the main two parties and to shake up his own party in the process.
On Friday he announced the appointment at a private meeting - at the London Wetlands Centre in Barnes - with leaders of Britain's green pressure groups , who emerged surprised and impressed with the new leader's knowledge of environmental issues and his professed commitment to them.
It is part of a deliberate attempt to recruit the party's most credible green voices. John Gummer, the Tories' respected former environment secretary, is to head the review group - charged with coming up with an entirely new set of policies over the next 18 months - and Peter Ainsworth, probably the leading MP on green issues in the House, has been made shadow Environment Secretary.
But it is Goldsmith's appointment that has caught the public imagination. Jemima Khan's tall, handsome brother, is already a prominent figure, partly thanks to the gossip columns, and partly through his campaigning.
Born to Sir James and his third wife, Lady Annabel, Zac became interested in the environment through an "obsession" with Sir David Attenborough's wildlife programmes.
"As a child I grew up with his stuff. As you follow it you fall in love with the world. Then you learn it's all under siege."
He decided to do his bit, aged nine, by building a "budgerigar sanctuary" in the garden of the family home in Richmond. "I did not like the idea of birds in cages and so I took over an old chicken coop", he says. "Then I went round Richmond looking for people who no longer wanted to keep them as pets. I must have collected 20 birds; a few had been caged so long they could not fly.
"It worked; they bred, and their descendants are there in what is now my mother's garden."
Expelled from Eton after dope was found in his room, he did environmental work in Ladakh, in the Himalayas. After returning to Britain, seven years ago, he took over The Ecologist, founded by his uncle Teddy, a pioneering British environmentalist.
He had hardly known Teddy as a boy, though he is now a major influence, and had rarely read the magazine. But he sharpened it and gave it a campaigning edge. One early issue, on Monsanto, was pulped by its printers, apparently fearing legal action by the biotech giant. The ensuing row raised the magazine's profile and ignited anti-GM movements.
Goldsmith came to welcome libel threats, offering to finance their actions in the courts, to give the issue publicity.
Sir James too, supported green causes, usually secretly. He quietly funded the protesters at the public inquiry into Sellafield's notorious Thorp reprocessing plant, and channelled money for causes like the McLibel suit - McDonald's actions against two activists - through Zac.
"My account must have looked dodgy," he recalls. "I was getting a small income then but every so often huge sums would appear in it and then get paid out."
Zac himself funds environmental causes - and raises money for them (which he "hates") - concentrating on supporting organic and small-scale farming. He married Shererazade - the daughter of asset-stripper John Bentley and socialite Viviane Ventura - six years ago and they run an organic farm in Devon, and try to keep their three young children fed on chemical-free food.
But he has concluded that, for all their efforts, environmentalists have not been winning battles, and has rethought his attitude to politics. He still loathes Tony Blair ("Very slippery ... I would not trust him with my dog") and sees Labour as too authoritarian and centrist.
This year he joined the Tories, despite a record of equal contempt for their leaders. Five years ago he said of William Hague - now a fellow Cameron appointee as shadow Foreign Secretary: "I'd have to drug myself before I voted for him. Get drunk beforehand. And then wash myself afterwards."
He had added: "In 10 years' time I might be an eco-terrorist. But I'll take the most effective path, whatever that is."
He couldn't have imagined that the path would take him to the inner circles of the Conservative Party, whose parliamentary candidate list he joined this autumn. But he insists that both he and the party have changed.
"I did not think there was a need to get involved in politics, but I have changed my mind. And David Cameron is thinking of some pretty radical solutions on the environment. It looks as if the party is ready to go for it.
"I don't know what the reaction is going to be from the old guard, but I don't think that matters. A momentum is building."
He says he chose to join the Tories because of the chance to change their policies ("It's hard to influence a party in power: it gets so arrogant") and also because he believes his support for small-scale decentralised food and energy production, and a precautionary approach to pollution, makes him a natural Conservative.
He now has a good chance of becoming a Tory MP, following his grandfather, Frank, a friend of Winston Churchill.
Initially his and Mr Gummer's review group will concentrate on global warming, which Mr Cameron has gone out of his way to highlight in his first days as leader, raising it in his acceptance speech, and making it one of the two main themes, with education, of his first Prime Minister's Questions.
But the crunch is likely to come over the Government's review of the nuclear programme. Goldsmith is strongly against nuclear power, Gummer is in favour of it, though he feels it needs to prove its case. Peter Ainsworth is deeply sceptical, while Cameron is anxious not to appear anti-nuclear.
Mr Blair is unlikely to be able to get parliamentary support for his desire to build 10 new atomic plants without the Conservatives, and so the conclusion of the nuclear review will provide the crucial test of the greening of the Tories. And it will show whether the greatest punt of the young gambler - who plays poker in a private room at Annabel's every week - is going to pay off.
Born: 1975. Zac was the son of business tycoon Jimmy Goldsmith. He was Jimmy's fourth child and their bizarre family situation meant Jimmy split his time between France and England, among mistresses and wives who lived aware of each other. Zac's mother, Lady Annabel Goldsmith, was Jimmy's third wife.
Education: Zac attended Eton but was expelled from the school at the age of 17, after cannabis was allegedly found in his room. He got his A-levels at a Cambridge crammer and took an extended year out to the Himalayas.
Career: While working as a researcher at the International Society for Ecology and Culture, the firm took over The Ecologist. Goldsmith became letters editor and later took over as editor. He moved the offices back to London and enlisted the help of his Uncle Teddy - the previous owner. The magazine was then re-designed and became bigger and better. Goldsmith hopes to launch a US version soon.
Lucky break: Goldsmith would probably never have become editor of The Ecologist had it not been for his Uncle Teddy, who bought the paper in 1970.Reuse content