Five fire engines and around 35 firefighters were called to a fire at a range of portable cabins on Park Crescent Mews in Marylebone.
Part of the second floor of a four storey block of cabins was damaged by the fire. Two people left the site before the Brigade arrived, and there were no reports of any injuries.
The fire is believed to be accidental but the cause is still under investigation.
The Brigade was called at 0443 and the incident was over for us by 0559. Fire crews from Kentish Town, Lambeth, Kensington and Shoreditch fire stations were at the scene.