Fifteen fire engines and around 100 firefighters have been called to a fire at a temple on Clifton Road in Southall.
Part of the first floor and roof of the building are alight.
Station Commander Richard Janssens, who is at the scene, said: “Firefighters are tackling a significant fire which has taken hold of the roof of the building.
“There is also residential accommodation at the rear of the building, but at at this stage, there are no reports of any people being involved.
“This is in a very busy part of Southall so there is a lot of traffic and we would advise motorists to avoid the area where possible.”
Firefighters were called at 12:29pm today and crews from Southall, Hayes, Hillingdon and Heston fire stations are currently at the scene.
The cause of the fire is not known at this stage.