Salil Shetty, Secretary General, Amnesty International

This year, Amnesty International passes a milestone; 50 years of campaigning on behalf of prisoners of conscience - speaking out for freedom.

And yet this 50th birthday is marked less by collective satisfaction than soul searching. The group's values and strategy have come under fire from insiders and outsiders.

Stephen Sackur speaks to Salil Shetty, head of Amnesty International's International Secretariat, and asks if one of the world’s highest profile campaign organisations has lost its way.