Adam Rutherford discusses the relationship between basic and applied scientific research with guests at the Hay Festival.

Adam is joined by the Astronomer Royal, Lord Martin Rees, physicist Professor Robbert Dijkgraaf, the director of the Institute for Advanced Studies at Princeton University and author of a new essay introducing On the Usefulness of Useless Knowledge, behavioural psychologist Professor Theresa Marteau of Cambridge University and geneticist and writer Professor Steve Jones of University College London.