Naomi Campbell on her activism for Africa, Nelson Mandela’s wisdom, and Karl Lagerfeld

• ‘I didn’t know anything’, British supermodel says of modelling for Lagerfeld at 16, and recalls the support Linda Evangelista and Christy Turlington gave her
• She talks about her mission to help Africa and African fashion and confesses that, at 49, she doesn’t know what to do with herself if she has a day off