This article was reproduced with the kind permission
of the British Broadcasting Corporation
27 November 2007, 13:59 GMT
Anthony Cooper, 37, from Brighton, East Sussex, has denied starting the fire in which Janet Chesworth, 65, of Sedgley, West Midlands, died in January 2006.
Taxi driver Craig Ward told Cape Town Regional Court he was parked at the foot of Table Mountain at the time.
He said a flame began "within seconds" of the cigarette being discarded.
"He threw his leftover cigarette on to the dry grass and within seconds a flame started due to the condition of the grass and strong winds," Mr Ward said.
Mrs Chesworth had been hiking with her daughter at the time of the fire, and died of smoke inhalation.
More than 150 firefighters together with water-carrying helicopters struggled to bring the blaze under control.
Mr Cooper is accused of arson and culpable homicide.
The trial continues.