Stephen Sackur speaks to Kgalema Motlanthe, former interim president of South Africa and stalwart of the African National Congress. The ANC's current party leader Jacob Zuma will quit at the end of 2017, with a host of candidates including his ex-wife vying to replace him. Is the ANC - the iconic movement of South Africa's liberation struggle - close to the end of its productive life? And are the most respected ANC members ready to contemplate a new political home? Show less