I abhor anything that constitutes torture. Water-boarding, its perfectly clear to me it is torture. I never supported extraordinary rendition to torture, always said that Guantanamo should be closed. There is no clash of ideals and pragmatism there.

What's now urgently needed [to stop environmental disaster] is the international political commitment to take action to avoid dangerous climate change.

The biggest opportunity in 2013 is in Africa. It has seven out of the ten fastest-growing economies in the world. In Nigeria alone there are 100 million people with mobile phones. In total, 300 million Africans - five times the population of Britain - are in the middle class.

If you decide to run for the leadership, you have to go through it with the people you love. But you also have to protect them and I am determined to protect my mum.

The science is getting worse faster than the politics is getting better.

Consuming three planets' worth of resources when in fact we have one is the environmental equivalent of childhood obesity - eating until you make yourself sick.

I think the wonderment of seeing my two sons developing makes me incredibly optimistic about human potential. It makes you think: 'My goodness. It's a miracle that's going on here. What could the human race do together?'