Six fire engines and around 40 firefighters were called to a fire at an electrical substation on Ludgate Hill in The City of London.
A section of the external wall and insulation of a substation was destroyed by fire. Around 150 people left a neighbouring office building. There were no reports of any injuries.
Station Commander James Ryan, who was at the scene, said: “The cabling of an underground substation was alight and produced a considerable amount of smoke which travelled into the basement of a neighbouring office building.
“The power was isolated, and firefighters removed parts of the pavement to gain access to the fire and expose the trunking in a void, which was around 1.5 metres deep.
“An aerial ladder was used to give incident commanders a bird’s-eye-view of the incident and road closures were in place whilst crews worked to make the scene safe.”
The Brigade’s Fire Investigators believe the fire was accidental and caused by the unsafe disposal of smoking materials.
The Brigade was called at 1653 and the fire was under control by 1848. Fire crews from Dowgate, Shoreditch, Whitechapel, Soho and Euston fire stations attended the scene.