Ideals survive through change. They die through inertia in the face of challenge.

The 21st century will not be about the battle between capitalism and socialism but between the forces of progress and the forces of conservatism.

Society works by putting opportunity and responsibility together.

Genetic modification has many different areas, for example in medicine, and Britain is at the leading edge of this new technology. I don't know, but people tell me, it could indeed by the leading science of the 21st century. All I say to people is: 'Just keep an open mind and let us proceed according to genuine scientific evidence.'

But the world is ever more interdependent. Stock markets and economies rise and fall together. Confidence is the key to prosperity. Insecurity spreads like contagion. So people crave stability and order.

If we are going to carry on growing, and we will, because no country is going to forfeit its right to economic growth, we have to find a way of doing it sustainably.

My office is on Twitter. I don't tweet myself - at least, not intentionally, but I probably should do.