Julian Assange, the co-founder of the whistleblowing website WikiLeaks - which is currently releasing over 250,000 confidential American diplomatic cables - is in the UK fighting extradition to Sweden where he is wanted on charges for sexual assault.
He joins Sir David to talk about a host of issues, from his personal situation to the role of WikiLeaks as a bastion of transparency, championing the right to reveal government secrets, when it is in the publics' interest.