In politics you learn to always smile.

Companies that pollute should be taxed so that a product's cost to society is reflected in the price of that product.

As someone with a deep faith in competition and the market, I also know that markets only work with tough enforcement of the rules that guarantee competition and fair play - and that the pressure to break those rules only gets stronger as the amount of money involved gets larger.

Why does it have to be politics? Is there a dynamism to that world and a theoretical capacity to do things that draws many talented people? Absolutely. Are there other ways to be involved and lead an interesting life? Of course.

When you're in office, there are tangible moments when you can see tangible successes.

I believe in an evolving Constitution. A flexible Constitution leaves room for us to consider not merely how the world once was, but how it ought to be.

The pace of global warming is accelerating and the scale of the impact is devastating. The time for action is limited - we are approaching a tipping point beyond which the opportunity to reverse the damage of CO2 emissions will disappear.