When is it OK to kill in self-defence?

South African law says that if faced with an attacker‚ people may defend themselves in proportion to the threat. But Gareth Newham, of the Institute for Security Studies, says using excessive force can lead to prosecution. ‘The checks and balances for self-defence are quite rigorous. You will have to demonstrate that you reasonably believed that your life was threatened‚ that you were going to die if you didn’t defend yourself’