This article was reproduced with the kind permission
of the British Broadcasting Corporation
28 November 2007, 20:59 GMT
Anthony Cooper, of Brighton, Sussex, has denied starting the fire on purpose in which Janet Chesworth, 65, of Sedgley, West Midlands, died in 2006.
Under cross-examination Craig Ward told Cape Town Regional Court he assumed it was a burning cigarette butt.
The defence say a piece of match used by Mr Cooper, 37, flew on to grass.
Mr Ward had told the court he was parked at the bottom of the mountain, near the cable car station, looking for fares when he saw Mr Cooper walking down the slope smoking.
Stamp out blaze
He said he then saw that he had "flicked something" out of his car window on to the grass.
But under cross examination he conceded that he merely assumed it was a burning cigarette butt.
Fellow taxi driver Jack Furter told the court he did see Mr Cooper throw his burning cigarette on to dry grass and insisted his own version was correct.
He said: "As Cooper closed the boot of his car I saw him toss a burning cigarette butt on to the grass."
Mr Further said there was no chance anyone could have tried to put out the fire and he had alerted the rangers.
Earlier Reuben Liddell, defending, said Mr Cooper tried to stamp out the blaze which had started when a flaming piece of a match he used to light a cigarette flew out of his car and on to the grass.
He said Mr Cooper denied smoking while walking and had first tried to extinguish the fire, then called for help but no one responded.
Mr Liddell said he then rang an emergency number on his mobile phone.
Mrs Chesworth had been hiking with her daughter at the time of the fire in January 2006, and died of smoke inhalation.
More than 150 firefighters, together with water-carrying helicopters, struggled to bring the blaze under control.
Officials in South Africa said the death toll could have been higher if high winds had not closed the mountain's cable car.
Mr Cooper is accused of arson and culpable homicide. He denies both charges.
The trial has been adjourned until 10 December.