Four fire engines and around 25 firefighters were called to reports of a fire in the basement of an office block in Gracechurch Street, City of London.
A fire suppression system actuated and helped to suppress the fire.
The Brigade was called at 1435 and the fire was under control by 1528. Crews from Dowgate, Whitechapel, Shoreditch and Dockhead Fire Stations were at the incident.
The cause of the fire is under investigation.