We're all here today to celebrate the launch of the UK's first indices for green companies - the Environmental Opportunities Indices.
As many of you will know, the Conservative Party has been working with the LSE and the FTSE on this project right from the beginning.
I proposed the creation of a green index in a speech to Imperial College London last February, and I set up a working group headed by Stanley Fink to work with the LSE to take this proposal forward.
It's great to see these ideas now built on and put into practice, and I deeply grateful to the LSE for their leadership and hard work in taking this proposal and running with it.
I firmly believe that in the years to come, this innovation will be seen as a milestone towards making the City of London the best place in the world for green investment - and the world centre for green finance.
It's policies like this that will help to bring to an end the stale argument that we have to choose between economic growth and the environment.
I have always considered this to be a false divide.
As I've said on many occasions, economic growth and environmental sustainability can go hand in hand.
Let me give you just two examples.
At a time when business is tough, the Environment Agency has calculated that British manufacturing could increase its profits by up to £3 billion if environmental best practices become standard across the board.
And with employment in the UK falling at the fastest rate since records began, the International Labour Organisation has calculated that 20 million new jobs could be created globally in the green technology sector in the years ahead.
So there is a massive opportunity out there for British companies to go green and lead the world in developing new environmental technologies.
But, of course, these technologies need to be financed.
So there is also a great opportunity for the City of London to create new sources of investment and wealth as the global centre of green finance.
A recent report found that the global market for carbon alone is now worth over £30 billion, and that figure is set to grow rapidly in the years ahead.
According to the head of environmental markets at Barclays Capital:
"Carbon will soon be the world's biggest commodity market, and it could become the world's biggest market overall."
So if we make the most of these opportunities, that will not only be good for the economy, it will be good for the environment too.
This approach will form part of the new British economic model that the Conservative Party is proposing.
We want to see a more stable and more balanced low carbon economy.
That means making the transition from an economy built on debt to one built on savings and investment.
But it must also mean the City, and the economy as a whole, becoming greener and more sustainable.
The Environmental Opportunities Indices being launched today help to show us how this transformation can take place.
Above all it shows us how the London Stock Exchange, and the City in general, can be the world leader in a whole new field of finance.
And how we can all lay a path towards a greener and more prosperous future.