<p>We now live longer today than at any time in history. In the UK, more people are aged over sixty-five than under sixteen and by 2050, over a third of the developed world will be over sixty. How should we deal with this phenomenon? What are the scientific reasons for ageing? And can - or should - we prevent it?<br>Lewis Wolpert, distinguished biologist and octogenarian, explores the scientific background and the implications of our ageing popul...