© X/RodCam24The Met declared a critical incident following the blaze on Thursday
The fire started during the morning rush hour in Wimbledon and the electric bus was quickly evacuated.
Transport for London (TfL) said electric buses on route 200, which runs between Raynes Park and Mitcham, had been removed from service "as a precaution".
Another bus caught fire on Friday, which TfL said was "unrelated".
Comment: As you will read below it was also an electric bus.
On Thursday, emergency services were called to the junction of Wimbledon Hill Road and Alwyne Road in Wimbledon shortly after 07:20 GMT.
The Met Police declared a critical incident and confirmed that no injuries were reported.
Tom Cunnington, TfL's head of bus business development, said it was working with the operator, London General - a subsidiary of Go-Ahead London - and the bus manufacturer, Switch, to "investigate" what happened.
Go-Ahead London confirmed it had "withdrawn the vehicle type in question" and was working with relevant authorities to "establish the facts".
Comment: 'The facts' seem to be that the technology for electric vehicles, at the moment, is such that they are liable to burst into flames for a variety of reasons.
Hybrid bus fire
On Friday, a hybrid double-decker bus was destroyed in a fire just before 07:00 GMT on Factory Road in North Woolwich.
No passengers were on the out-of-service vehicle and there were no reports of injuries, Mr Cunnington said.
"We are working with the operator, Go-Ahead, and the manufacturer, Alexander Dennis, to investigate the cause of this fire," he said.
"London's bus network remains safe to use and we have no reason to suspect that this fire on a hybrid bus was linked to an earlier incident on an electric bus in Wimbledon.
Comment: The two incidents aren't linked? They're both electric vehicles that burst into flames within 48 hours of each other.
"TfL and the bus operators will not hesitate to take action if required to ensure the bus network remains safe."
The cause of the fire is under investigation, the London Fire Brigade said.
Now, would they lie ... ? I'm sure of that, and it definitely reassures me ...