Mark Lynas - Environmental campaigner and author

Stephen Sackur talks to Mark Lynas, a veteran green activist who once led a campaign to vandalise experimental genetically modified crops. But that was then - now he says that GM technology is entirely safe, and is a necessity if we are to feed the planet. He has made a similar U-turn on nuclear power too. The zeal of the convert can be a factor not just in religion but also in scientific debate. He says that he has junked ideology in favour of hard science. But is it really as simple as that?