Comment: I won't back Gordon's great Heathrow con

Gordon Brown's attitude to Heathrow expansion, like his attitude to everything else, is driven by political calculation, not conviction.

Whether it's the issues he chooses to prioritise, the positions he takes on those issues or the causes that he champions, it's never about the national interest, it's never about making life better for people and addressing their concerns, it's always about creating "dividing lines" with his opponents - whether it's the Conservative Party or his opponents inside Labour. This was the case with the 10p tax fiasco, where he was trying to pose a tax cutter, and the issue of 42 days, where he was posing as tough on terror. With Brown it's always about the politics, not the policy.

This partisan and short-term mindset is why the Prime Minister has made such a fetish of the need for a third runway at Heathrow, constantly citing it as an example of making "the right longterm decisions". For those who haven't yet understood how things work in Brown's Britain, this is what's going on.

The Prime Minister has noticed that since I became leader of the Conservative Party, I have pushed the environment higher up the political agenda. But rather than engage with the green agenda, either driving it forward in government or indeed openly rejecting it, he has decided to play politics with it.

So he tries to define the issue of a third runway as a "tough choice" between the economy and the environment. If you back a third runway you're on the side of jobs, business and prosperity. If you don't, you're somehow not serious, putting lightweight environmental concerns ahead of the economy.

What a way to plan for the future. Again, it's all about the politics, not the substance of the argument.

First, his economic case for Heathrow expansion is unravelling day by day. It's based on making Heathrow an even bigger "hub" airport, with a massive increase in the number of transfer passengers. As Bob Ayling, former chief executive of British Airways, has said: "This is a classic exercise in misguided central planning." Forget for a minute that the economic value of transfer passengers is hotly disputed - after all, they often spend only the price of a cup of coffee in the UK. The real issue is the "hub" model itself, which contributed to the bankruptcy of almost every US airline and Sabena in Europe too.

Why? Because passengers are people, not statistics. They react to airport delays, missed connections and lost luggage with their feet and don't come back. And after the recent fiasco of Terminal 5, there must be severe doubt about whether the Government and BAA are even capable of managing the expansion of Heathrow to cope with more than 700,000 flights a year by 2030.

I think the whole country can agree that the most important priority for Heathrow is making it better, not bigger. That means looking seriously at competition issues surrounding BAA and how our airports are managed.

Second, and much more important, is that Gordon Brown just doesn't get the environmental agenda. He thinks we've got to choose between fighting climate change and boosting our economy. For him, it's one or the other. The reality is that it must be both.

After all, when oil is hitting $140 a barrel and everyone is feeling the pinch when they fill up their car or pay their gas bill, it's not that we can't afford to go green - it's that we can't afford not to go green.

In an economic downturn, and with the cost of living rising, we need to pursue the green agenda in a way that strengthens the economy and strengthens family finances. Today I've been setting out how we can make this reality. It's called the Blue/Green Charter, and it has five elements.

We should boost technological change by harnessing the power of markets and innovation. For example, it's obvious we'll never become truly green if our cars continue running exclusively on petrol or diesel. And it's equally obvious that we should never expect people to give up driving. So we need clean cars - and to get there, we will set an aggressive emissions target for all new cars. Every car developer will know that unless they get researching and developing, they won't survive. Brown's alternative is a tax on the Ford Mondeo you bought seven years ago - just another stealth tax.

Second, green taxes should be replacement taxes, not new ones. Gordon Brown just doesn't get this. He sees green taxes as a way of getting more money for the Government. We understand that green taxes can change behaviour - but every penny raised should be offset against tax reductions elsewhere. That's how we can go green while helping families save money.

The third part of the plan is to keep the lights on by securing our energy supplies. We simply cannot keep relying on unstable countries for our oil and gas. It's not just bad for the environment and our cost of living - it's bad for our national security. That's why we've developed plans for a new system of decentralised energy so it makes economic sense for people to generate their own energy - and get paid for it. It's worked in Germany where they now employ more than 200,000 in the renewable energy sector, and it can work here too.

Fourth, we must prioritise energy efficiency. Of course, much of this involves individuals being responsible with their energy use. But the latest thinking in how to influence behaviour suggests that government can do a lot more to help. Research has shown that when people see that they're using more energy than others, they bring their own use down. That's why we will make sure every gas and electricity bill has information on it showing each household how their energy use compares with other households.

The fifth point on our Blue/Green Charter is getting transport right - and this comes back to Heathrow. When we've got gridlocked roads and slow, packed and expensive trains, we should be putting our energies into seeing whether we can get high-speed rail, and finding ways to unlock our transport infrastructure and get Britain moving.

So if we can just get beyond Gordon Brown's partisan posturing, we can see that the real dividing line is not between the environment and the economy. It's between the past and progress. I know which side I'm on. And I know which side our country should be on.