The man on the phone was trying to help. "We can be as discreet as you like." I will admit I was sorely tempted. Discretion offered the chance to avoid embarrassment, to follow my impulses secretly, away from prying eyes. But what if I was found out? I felt a frisson of danger, of the sort undercover agents must feel when they come close to being unmasked on a mission. But my mind was made up. "No," I said. "I'd rather everyone knew." I felt the release of honesty wash over me: I'd joined the Conservative Party's working group on climate change.
This is not, I hasten to add, the same as joining the Conservative Party. My Green Party membership card sits intact in my wallet, though I did half expect it to spontaneously combust in response to my treachery. I also wish to make it quite clear that I'm not being paid a penny. No one has even offered to take me out to lunch. It's entirely voluntary, not because I'm a sucker - but because I'm doing it for the Cause.
I'm not alone. There is a growing sense across the ranks of climate-change activists that Tony Blair's government has failed on the issue, and that there is little point in defending it. Just follow the money: Labour's spending on road-building has doubled since 1999 and now totals more than £1bn a year. This must be roughly ten times the paltry sums the government spends on tackling climate change directly. The minister for roads, Stephen Ladyman, talks about new bypasses to "relieve" congestion, which suggests that he fails to appreciate the long-established truism that new roads inevitably generate more traffic. The Newbury bypass, for example, has led to 50 per cent more car journeys around the town.
The "Battle of Newbury" was the high point of the anti-roads movement in the 1990s, a movement now remobilising in angry response to Labour's renewed love affair with roads. At a meeting in Birmingham on 10 June, a new generation of protesters from across the country gathered to plan how best to stop the bulldozers. The previous weekend I'd spoken at a national Campaign Against Climate Change meeting in London, where the anti-Blair feeling was palpable.
As our dependence on cars rises, so do their climate-changing carbon-dioxide emissions. CO2 releases are higher than at any time since Labour came to power, adding up to a terrifying 732 million tonnes per year. Road transport emissions are soaring, having risen 13 per cent since 1990. Along with aircraft pollution, the roads sector is our fastest-growing contributor to global warming. The Newbury bypass approach locks us into a model of car-centred consumption that spells disaster for our climate.
I'm not saying the Tories have the answer - just that David Cameron is moving in the right direction, while Labour is doing the reverse. Many Tories still don't get it. The policy group on economic competitiveness, led by John Redwood, issued absurd proposals aimed at giving further priority to the car, suggesting that bus lanes be open to all traffic at peak times, speed limits be raised, cyclists banned from the road and pedestrian crossings banished to dimly lit underpasses. All these proposals contradict evidence collected by the Conservatives' quality of life group. That the party is torn both ways illustrates the challenge society faces in trying to reconcile sustainability with economic growth.
I have one proposal that I'm looking forward to putting to my fellow members of the climate-change working group - carbon rationing. Instead of the government dictating every aspect of our lives, from what fridge we buy to where we go on holiday, carbon rations would delegate these decisions to each individual. We would each get an allocation, renewed every year, within the context of a declining overall national and international budget of greenhouse-gas emissions. This enshrines the principle of equality, which Cameron seemingly supports, but it also releases the power of the market. With the carbon rations fully tradeable, individuals who use less than their allocation could sell their spare share and pocket the difference. The market would thereby provide incentives for climate-friendly lifestyles. If the Tories want to go green, this is how to do it.
I'm not suggesting that the Conservatives can be transformed into a party of deep ecologists. But there is no doubt that Cameron has changed the political landscape simply by taking global warming seriously. And instead of talking nonsense about endogenous growth theory, Gordon Brown is, all of a sudden, having to mug up on his climate science.