Five things Barack Obama said in Mandela lecture

Obama said five key points in his Nelson Mandela lecture, made to the world's media and an audience of some 15,000 people in South Africa's main city, Johannesburg. [Courtesy]

Barack Obama has used his first high-profile speech since stepping down as US president to take swipes at "strongman politics" and politicians' disregard for the facts.

His comments are seen as thinly veiled criticism of the current US administration's use of what has been described as "alternative facts".