Dr Peter Friedland was one of several doctors who treated South African leader Nelson Mandela in the years after he left the presidency. In this exclusive extract from his memoir, Friedland recalls the dramatic circumstances of the first time he came close to Mandela.

Nothing much happens in the South African Army after 3.30 on Friday afternoons. On one such afternoon in February 1991, I had just seen my last patient and was packing up when my desk phone rang. I’d been in the army for almost eight months as a medic and was running an ENT (ear, nose and throat) clinic for military personnel. I picked up. Offering no pleasantries, a male voice barked orders in Afrikaans: “Present yourself in officer’s uniform to the lieutenant colonel at the Witwatersrand High Command at the city barracks in Twist Street at 16.30.”