He believes that markets would deliver greener outcomes if they went with the grain of what people want. “Local food should not be a niche luxury thing. What is rigging the market in the wrong way? There are so many hidden subsidies. We spend £250 million on cleaning pesticides out of drinking water. We pay twice for food: once at the checkout and again for the infrastructure. We need to get closer to a free market system and remove artificial supports.”

Energy markets, he believes, are also rigged. The US Congress recently turned down a Bill which would have “required carmakers to adhere to higher fuel-efficiency standards. It would have cost them 2-3 per cent more but they would have used 20 per cent less oil.”

He adds: “Even if you take every last drop of oil from Alaskan oilfields you will only get six months’ worth of oil in the US. We are destroying the last great wilderness for six months of oil.

“Getting serious about energy efficiency would give you that saving overnight. It could cut our energy use by between 35 per cent and 80 per cent, depending on who you talk to. If every light bulb in England was energy efficient, on current technology we would save one and a half power plants.”

He rattles off more statistics. It is like trying to keep up with a pneumatic drill. “You are obsessive,” I say. So how does he switch off? “It’s one of the reasons I like poker. Poker is like meditation. I envy people in horse racing — bloodstock, the form, a world where everything makes sense. Not like the real world.”

He looks suddenly forlorn. Back in the real world, he deals with the same dilemmas as all of us. “I have read too much about how meat is produced to enjoy eating it if I don’t know where it comes from. I’m not a meat fundamentalist but there are certain labels I trust and restaurants where I know where it comes from.”

He loathes plastic toys: “They’re hideous, they smell, they’re unhealthy. My childen have lots of these things. If I give a present to my godchildren it will be a first edition book or a nice book. My children do not need more toys: they will not add to their lives but they will add to landfill. It doesn’t make me feel good to have a bin full of plastic junk at the end of the day.”

But he doesn’t want his children left out. “I don’t want them to feel marginalised. Peer pressure is incredibly powerful — I’d rather they were comfortable among their friends.”

He also dislikes jumbo jets, but not just for green reasons. “The environment is a good excuse not to go to conferences but my actual motivation is fear of flying. I have to take vast quantities of drugs — Rohypnol, Temazepam — to get on. I gave a speech at a New York fundraiser last year and I don’t remember anything. I have no idea what I talked about . . . I had lots of letters afterwards and I didn’t know how to reply.”

In America, he says, individual states are moving despite George Bush. “Arnold Schwarzenegger is well ahead of the game on climate change. He is making it fashionable for people on the right to care about these issues — as I think David Cameron will.” Goldsmith’s appointment as deputy chairman of the Conservative Party’s commission on the environment is “a dream opportunity for me”, although he had never met the new Conservative leader.

“The reason I am in politics now is that I have not managed to achieve anything like I had hoped to outside politics. I’ve had letters from some environmentalists saying you shouldn’t get into bed with the Conservative Party because their track record is not good. I can’t think of a single government with a good track record. If there is a 10-1 shot that they’d accept what we come up with, those are bloody good odds.”

But how will his radical views go down with Tories? “My job is to create cohesion, not to use the group to legitimise my views but to get others who know more to share their knowledge, to learn from other countries. In Ireland the tax on plastic bags looks like its working. Massachusetts uses 80 per cent less toxic waste than 10 years ago — we need to find out how.”

Won’t there be conflict over taxes? “I don’t envisage proposing any tax rise. I will be amazed if what we come up with is not revenue-neutral. It is not about increasing regulations but about shifting emphasis. Most environmentalists would come out with a huge increase in taxes, in regulations, and in the scale of government. I don’t agree. The Conservative Party doesn’t like forcing people to do anything and I don’t think we have to. It’s about enabling people to do what they want to do anyway — most of the obstacles are from bad governance. Which consumer wants actively to buy GM food? The US is dumping GM on starving countries and refusing to put labels on, to trick consumers into accepting something the free market would reject. Here we are paying for planes ready to be scrambled over Sizewell B at any moment and for a £74 billion nuclear waste bill even if we don’t build any new reactors. The CBI are terrible hypocrites — I regard myself as a greater free marketeer.”

Surely he would want to propose more regulation? “No one thinks they’re going to change the world by switching their light bulbs but if they knew you could push a button and make all houses change, everyone would push it. Government has to make that button.”

Will nuclear prove a sticking point? “I know the likelihood is that the Conservative Party will come out in favour of nuclear power. John Gummer (chairman of the commission) knows what is politically saleable and what’s not. But even if, in 18 months’ time, we come up with something that is rejected by the party, we will still have got a blueprint. And if parties are competing for this ground — a kind of arms race — it suggests the ground is worth competing for.”

We shall see if he can stay the course. I’d say it is odds on that the tough campaigner will find that he can also do political compromise.

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