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.
When he co-founded WikiLeaks he saw that he could encourage, through successful examples, people to step forward to reveal abuses by governments - to produce more justice. Subscribing to the motto that "courage is contagious", Assange claims not to be an anarchist; rather his modus operandi is to promote responsible governance.
Now his lawyers are concerned that he will end up in an American jail, either directly through extradition from the UK, or through extradition from Sweden.
Assange heavily implies that receiving a fair trial in Sweden is doubtful. Why was the most senior prosecutor in Sweden removed (and replaced) after he said there was "no evidence or even suspicion" of rape? Why do Swedish authorities refuse to provide British officials with any evidence of crimes Assange allegedly commited - including witholding the statements of the victims?
He is hesitant to blame his two accusers for their allegations against him, suggesting they could be innocently caught up in a greater political scheme.
This special episode of Frost over the World can be seen from Tuesday, December 21, at the following times GMT: Tuesday: 2330; Wednesday: 0830, 1430, Thursday: 1930.