In this year's final Christmas Lecture, Dr Alison Woollard from the University of Oxford, tackles a question that has intrigued scientists and natural philosophers for centuries. The cycle of life and death affects all cells, but Alison reveals a shocking truth - that 'cell death' plays an important part in life. It enables the development and survival of most multi-celled organisms from hedgehogs to humans.

The show’s own verdict is on its page.