The double-decker London bus burst into flames on the busy road eastbound as it passed near Wennington around 9am today (August 1).
The bus was on a test drive and was not carrying any passengers.
There were no reported injuries as the driver left the vehicle before firefighters from the London and Essex fire services arrived.
The A13 eastbound was closed with “severe delays” extending past Rainham and near to Dagenham.
The closure and recovery of the bus were left with Met Police after the fire service left, with cars trapped in the road closure being slowly released.
The A13 remains closed at the time of writing.
The cause of the fire is not known with TfL launching an investigation with bus operator Arriva.
A London Fire Brigade spokesperson said: “We were called at 0903 this morning to reports of a double-decker bus alight on the A13 near Wennington.
“Firefighters have attended and extinguished a fire that damaged most of the bus. There have been no reports of any injuries.
“The A13 eastbound carriageway was closed to allow crews to work safely and the incident is currently causing significant traffic disruption in the area.
“Two fire engines from Wennington and Dagenham fire stations attended the scene, alongside Essex County Fire & Rescue Service.”
Rosie Trew, TfL’s Head of Bus Service Delivery, said: “An out of service bus caught fire while on a road test on the A13 Thames Gateway.
“The fire was quickly brought under control. There were no customers on board and no reported injuries to the driver.
“We’re working closely with the bus operator, Arriva, to investigate the cause of a fire.
“We’re sorry for any disruption caused.”