Collapsing stock markets, melting ice caps, floods, tornadoes, terrorism . . . When it comes to bad news, we've never had it so good.

Perhaps it is time to be a little more optimistic? That's what Laurence Shorter decided. And that's why he set himself the challenge of meeting the world's most cheerful people. Surely with the help of Desmond Tutu, Richard Branson and Bill Clinton, Laurence can find the secret to inner happiness.

But first things first - how on Earth is he going to get to meet them?