The idea that we are one step from calamity is as old as history itself. Every step on the road of progress has been countered by those who think that we should keep to a primitive lifestyle. But despite the fact that they've been proved wrong, the pessimists are undeterred by their abysmal record. Today, industrialisation, GM crops, scientific medicine, nuclear power and the car are held up as harbingers of doom. But will pesticides kill off life in our oceans? Will chemicals in food poison us all and invisible rays from power cables give us cancer? Stanley Feldman, a professor at Imperial College of Medicine, and Vincent Marks, editor of Panic Nation and an expert on diabetes, examine the evidence.